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Synthesis of amides


Reactions including a hydrolysis, oxidation, or rearrangement





Oxidative Amidations

Name Reactions

Schmidt Reaction

Schotten-Baumann Reaction

Ugi Reaction

Recent Literature

(2-(Thiophen-2-ylmethyl)phenyl)boronic acid is a a highly active catalyst for direct amidation between carboxylic acids and amines at room temperature for a large range of substrates. Slightly higher temperatures are required for challenging starting materials. Aliphatic, α-hydroxyl, aromatic, and heteroaromatic acids as well as primary, secondary, heterocyclic, and even functionalized amines can be used.
T. M. El Dine, W. Erb, Y. Berhault, J. Rouden, J. Blanchet, J. Org. Chem., 2015, 80, 4532-4544.

A commercially available thianthrene boron acid catalyzes a versatile dehydrative amidation. The catalyst shows high catalytic activity to both aliphatic and less reactive aromatic carboxylic acid substrates, including several bioactive or clinical molecules with a carboxylic acid group.
B. Pan, D.-M. Huang, H.-T. Sun, S.-N. Song, X.-B. Sun, J. Org. Chem., 2023, 88, 2832-2840.

5-methoxy-2-iodophenylboronic acid (MIBA) is kinetically very active in a catalytic, direct amidation employing free carboxylic acids and amines providing high yields of amide products in short reaction times under mild conditions at ambient temperature in the presence of molecular sieves. A possible catalytic cycle is based on the presumed formation of an acylborate intermediate.
N. Gernigon, R. M. Al-Zoubi, D. G. Hall, J. Org. Chem., 2012, 77, 8386-8400.

Stable and easily accessible triflylpyridinium reagents mediate an effective synthesis of a broad range of amides and esters at ambient temperature within 5 min. In addition, a flow process enables a scalable synthesis of peptides and esters. Moreover, excellent chirality retentions are presented during activation of carboxylic acid.
D. Chen, L. Xu, B. Ren, Z. Wang, C. Liu, Org. Lett., 2023, 25, 4571-4575.

Ammonia-borane serves as an efficient precatalyst for the direct amidation of both aromatic and aliphatic carboxylic acids. This method is efficient with equimolar amounts of the coupling partners and offers high functional group tolerance and chromatography-free purification.
P. V. Ramachandran, H. J. Hamann, Org. Lett., 2021, 23, 2938-2942.

Tetramethyl orthosilicate (TMOS) is an effective reagent for direct amidation of aliphatic and aromatic carboxylic acids with amines and anilines in very good yields. The amide products are obtained in pure form directly after workup without the need for any further purification. A silyl ester as the putative activated intermediate is observed by NMR methods.
D. C. Braddock, P. D. Lickiss, B. C. Rowley, D. Pugh, T. Purnomo, G. Santhakumar, S. J. Fussell, Org. Lett., 2018, 20, 950-953.

Triphenylphosphine oxide catalyzes amidation and esterification for an efficient synthesis of dipeptides, amides, and esters in good yields in less than 10 m without racemization. This reaction is applicable to challenging couplings of hindered carboxylic acids with weak nucleophiles amines or alcohols.
J.-W. Ren, M.-N. Tong, Y.-F. Zhao, F. Ni, Org. Lett., 2021, 23, 7497-7502.

The combination of trimethylacetic anhydride and catalytic amounts of potassium tert-butoxide mediates an amination of carboxylic acids with DMF as a dimethylamine reagent to provide N,N-dimethylamides. The applicability of this protocol is demonstrated by late-stage dimethylamidations of complex drug molecules.
Y. Huang, J. Zhang, Synthesis, 2022, 54, 3595-3604.

Borane-trimethylamine is an efficient reducing agent for the selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline serves as a highly efficient catalyst for the methylation of various secondary amines, whereas in its absence, the formylation of primary and secondary amines was achieved in high yield with high chemoselectivity.
Y. Zhang, H. Zhang, K. Gao, Org. Lett., 2021, 23, 8282-8286.

Ball milling of aromatic, heteroaromatic, vinylic, and aliphatic esters with ethanol and calcium nitride provides the corresponding primary amides in good yields. The transformation is compatible with a variety of functional groups and maintained the integrity of a stereocenter α to carbonyl.
J. Gómez-Carpintero, J. D. Sánchez, J. F. González, J. C. Menéndez, J. Org. Chem., 2021, 86, 14232-14237.

The L-proline-based amphiphile PS-750-M enables extremely fast amide couplings in water mediated by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide (without hydroxybenzotriazole). Product precipitation and isolation by filtration completely avoids the use of organic solvent. This methodology avoids product epimerization and is scalable.
S. Sharma, N. W. Buchbinder, W. M. Braje, S. Handa, Org. Lett., 2020, 22, 5737-5740.

A simple and metal-free method for the direct formation of dialkylamides from carboxylic acids employs N,N-dialkylformamides as amine source. The one-pot reaction is promoted by propylphosphonic anhydride (T3P®) in the presence of 0.5 equivalents of HCl.
L. Bannwart, S. Abele, S. Tortoioli, Synthesis, 2016, 48, 2069-2078.

NDTP is an unprecedented mild, nonirritating, conveniently available, and recyclable coupling reagent, which activates carboxylic acids via acyl thiocyanide and enables a rapid amide and peptide synthesis at very mild conditions. In addition, the methodology is compatible with Fmoc-SPPS.
Y. Li, J. Li, G. Bao, C. Yu, Y. Liu, Z. He, P. Wang, W. Ma, J. Xie, W. Sun, R. Wang, Org. Lett., 2022, 24, 1169-1174.

A palladium-catalyzed N-acylation of tertiary amines by carboxylic acids produces the corresponding amides in very good yields via cleavage of a C-N bond. Both aromatic and aliphatic acids served well as the acylating reagents.
Z. Li, L. Liu, K. Xu, T. Huang, X. Li, B. Song, T. Chen, Org. Lett., 2020, 22, 5517-5521.

Amides were produced from carboxylic acids and amines in the presence of XtalFluor-E as an activator. Optically active amines and/or carboxylic acids were not epimerized/racemized during the process and even poorly reactive carboxylic acids can be transformed to amides.
A. Orliac, D. G. Pardo, A. Bombrun, J. Cossy, Org. Lett., 2013, 15, 902-905.

The reaction of amine-boranes as dual-purpose reagents with aliphatic and aromatic carboxylic acids provides amides in very good yields. Delivery of gaseous or low-boiling amines as their borane complexes provides a major advantage over existing methodologies.
P. V. Ramachandran, H. J. Hamann, S. Choudhary, Org. Lett., 2020, 22, 8593-8597.

A highly reactive ynamine, generated in situ by UV irradiation of an aminocyclopropenone, mediates dehydration condensations of carboxylic acids and amines to provide amides. This reaction is completely controllable by the ON/OFF states of a UV lamp.
K. Mishiro, Y. Yushima, M. Kunishima, Org. Lett., 2017, 19, 4912-4915.

Ynamides as novel coupling reagents enable a highly efficient, two-step, one-pot synthetic strategy for amides and peptides under extremely mild reaction conditions. Importantly, no racemization was detected during the activation of chiral carboxylic acids. Excellent amidation selectivity toward amino groups in the presence of -OH, -SH, -CONH2, ArNH2, and the NH of indole was observed.
L. Hu, S. Xu, Z. Zhao, Y. Yang, Z. Peng, M. Yang, C. Wang, J. Zhao, J. Am. Chem. Soc., 2016, 138, 13135-13138.

An effective protocol for a waste-minimized, environmentally benign thermal condensation of carboxylic acids with amines has been identified. Fourteen examples demonstrate the applicability of this procedure to aliphatic, aromatic and heteroaromatic carboxylic acids and primary and secondary aliphatic as well as aromatic amines. The approach leads to the corresponding amides in good yields.
L. J. Gooßen, D. M. Ohlmann, P. P. Lange, Synthesis, 2009, 160-164.

Nanosized sulfated titania was prepared by a sol-gel hydrothermal process. The nanoparticles showed high catalytic activity in a direct amidation of fatty acids as well as benzoic acids with various amines under solvent-free conditions.
M. Hosseini-Sarvari, E. Sodagar, M. M. Doroodmand, J. Org. Chem., 2011, 76, 2853-2859.

The mild combination of T3P (n-propanephosphonic acid anhydride) and pyridine enables a low-epimerization amide bond formation. This robust and practical method is general for the coupling of various racemization-prone acid substrates and amines, including relatively non-nucleophilic anilines, and provides amides in high yields with very low epimerization.
J. R. Dunetz, Y. Xiang, A. Baldwin, J. Ringling, Org. Lett., 2011, 13, 5048-5051.

A broadly applicable method for amide C-N and ester C-O bond formation is based on formylpyrrolidine (FPyr) as a Lewis base catalyst and trichlorotriazine (TCT) as a cost-efficient reagent for OH-group activation. The new approach is distinguished by excellent cost-efficiency, waste-balance, scalability, and high levels of functional group compatibility.
P. H. Huy, C. Mbouhom, J. Org. Chem., 2019, 84, 7399-7406.

Use of uronium salt (1-cyano-2-ethoxy-2-oxoethylidenaminooxy)dimethylaminomorpholinocarbenium hexafluorophosphate (COMU) as a coupling reagent, 2,6-lutidine, and TPGS-750-M enables a general, mild, and environmentally responsible method for the formation of amide/peptide bonds in an aqueous micellar medium. The aqueous reaction medium is recyclable leading to low E Factors.
C. M. Gabriel, M. Keener, F. Gallou, B. H. Lipshutz, Org. Lett., 2015, 17, 3968-3971.

The coupling reagent ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o-NosylOXY) produces only byproducts that can be easily recovered and reused for the synthesis of the same reagent, making coupling reactions to yield amides, hydroxamates, peptides, and esters more environmentally friendly and cost-effective.
D. Dev, N. B. Palakurthy, K. Thalluri, J. Chandra, B. Mandal, J. Org. Chem., 2014, 79, 5420-5431.

An efficient amidation of carboxylate salts with either free amines or their ammonium hydrochloride salts can be achieved in very good yields using HBTU in combination with Hünig’s base in 1-2 h. The protocol is valuable for the coupling of carboxylates for which the corresponding carboxylic acids or acyl chlorides are unstable. Addition of carbon dioxide to a lithiated terminal alkyne enables the synthesis of acetylenic amides in one pot.
J. D. Goodreid, P. A. Duspara, C. Bosch, R. A. Batey, J. Org. Chem., 2014, 79, 943-954.

A manganese(I)-catalyzed reaction of a wide range of aromatic, aliphatic, and heterocyclic esters, even fatty acid esters with a diverse range of primary aryl amines, primary alkyl amines, and secondary alkyl amines provides amides in good yields.
Z. Fu, X. Wang, S. Tao, Q. Bu, D. Wei, N. Liu, J. Org. Chem., 2021, 86, 2339-2358.

Readily available N-acylbenzotriazoles efficiently acylate aqueous ammonia and primary and secondary amines to give primary, secondary, and tertiary amides in very good yields.
A. R. Katritzky, H.-Y. He, K. Suzuki, J. Org. Chem., 2000, 65, 8210-8213.

Readily available N-acylbenzotriazoles efficiently acylate aqueous ammonia and primary and secondary amines to give primary, secondary, and tertiary amides in very good yields.
A. R. Katritzky, H.-Y. He, K. Suzuki, J. Org. Chem., 2000, 65, 8210-8213.

An amide formation using primary amines and potassium acyltrifluoroborates, that proceeds rapidly in water, is promoted by simple chlorinating agents. The reaction is fast at acidic pH and tolerates alcohols, carboxylic acids, and even secondary amines in the substrates. It is applicable to the (late-stage) functionalization of primary amides, sulfonamides, and other N-functional groups that typically resist classical acylations.
A. O. Gálvez, C. P. Schaack, H. Noda, J. W. Bode, J. Am. Chem. Soc., 2017, 139, 1826-1829.

Tetrakis(dimethylamido)diboron and tetrahydroxydiboron catalyze a simple and highly efficient condensation of aromatic carboxylic acids with amines to provide aryl amides. This catalytic approach avoids the use of stoichiometric or additional dehydrating agents.
D. N. Sawant, D. B. Bagal, S. Ogawa, K. Selvam, S. Saito, Org. Lett., 2018, 20, 4397-4400.

A degradable 1,3,5-triazo-2,4,6-triphosphorine (TAP) motif enables a dehydrative formation of amide bonds between diverse combinations of aromatic carboxylic acids and amines. The underlying reaction mechanism was investigated, and potential catalyst intermediates were characterized.
. S. Movahed, D. N. Sawant, D. B. Bagal, S. Saito, Synthesis, 2020, 52, 3253-3262.

An electrochemical amidation of benzoyl hydrazine/carbazate and primary/secondary amine as coupling partners proceeds under metal-free and exogenous oxidant-free conditions produces only N2 and H2 as byproducts. Mechanistic studies reveal the in situ generations of both acyl and N-centered radicals.
T. Alam, A. Rakshit, H. N. Dhara, A. Palai, B. K. Patel, Org. Lett., 2022, 24, 6619-6624.

A mild method for N-acylation of primary and secondary amines with α-diketones in high yield is induced by ultraviolet (UV) light at room temperature. This system can also be applied to the synthesis of several amino acid derivatives. Mechanistic studies show that benzoin is generated in situ from benzil under UV irradiation.
Z. Xu, T. Yang, N. Tang, Y. Ou, S.-F. Yin, N. Kambe, R. Qiu, Org. Lett., 2021, 23, 5329-5333.

Ynoates as novel coupling reagents enable a highly efficient and simple protocol for the direct amidation of carboxylic acids in very good yields via in situ α-acyl enol ester intermediates formation under mild reaction conditions.
X. Xu, H. Feng, L. Huang, X. Liu, J. Org. Chem., 2018, 83, 7962-7969.

Electrophilic activation of carboxylic anhydride using methanesulfonyl chloride is an efficient method for nucleophilic acylation, which increases product yield by restricting the formation of corresponding acid as a side product. The developed protocol enables one-pot nucleophilic acylation of anhydrides with several types of N- and S-nucleophiles in high yield demonstrating appreciable functional group tolerance.
V. Kumar, A. Rana, C. L. Meena, N. Sharma, Y. Kumar, D. Mehajan, Synthesis, 2018, 50, 3902-3910.

A chromium-catalyzed activation of acyl C-O bonds with magnesium enables an amidation of esters with nitroarenes in the presence of chlorotrimethylsilane as additive. The reaction provides a step-economic strategy to the synthesis of important amide motifs using inexpensive and air-stable nitroarenes as amino sources.
L. Ling, C. Chen, M. Luo, X. Zeng, Org. Lett., 2019, 21, 1912-1916.

B2(OH)4 mediates a reductive transamidation reaction between N-acyl benzotriazoles and organic nitro compounds or NaNO2 under mild conditions in H2O as solvent. N-Deuterated amides can be synthesized when conducting the reaction in D2O. A reasonable reaction mechanism involves bond metathesis between the AcBt amide and an amino boric acid intermediate.
J. Bai, S. Li, R. Zhu, Y. Li, W. Li, J. Org. Chem., 2023, 88, 3714-3723.

An organic photoredox catalyst promotes a metal-, base-, and additive-free amide bond formation reaction in high yields. This green approach offers a broad substrate scope, good compatibility with water and air, and tolerates functional groups such as alcohols, phenols, ethers, esters, halogens, or heterocycles.
W. Song, K. Dong, M. Li, Org. Lett., 2020, 22, 371-375.

A method for N-(hetero)arylamide synthesis based on rarely explored amine activation, rather than classical acid activation, shows a broad scope including challenging amides. The activated amines are easily prepared using a three-component reaction with commercial reagents.
Y.-P. Zhu, S. Sergeyev, P. Franck, R. V. A. Orru, B. U. W. Maes, Org. Lett., 2016, 18, 4602-4605.

The use of sulfinylamides generated in situ by the reaction of pure amines with prop-2-ene-1-sulfinyl chloride enables an efficient amidification of carboxylic acids. The method allows the conversion of aliphatic acids, including pivalic acid, aromatic acids, and primary and secondary amines and tolerates acids bearing unprotected alcohol, phenol, and ketone moieties without α-epimerization.
J. Bai, B. K. Zembrón, P. Vogel, Org. Lett., 2014, 16, 604-607.

The combination of dichloro(methyl)(3,3,3-trifluoropropyl)silane (MTFPSCl2) and imidazole mediates an amidation of amino acids. MTFPSCl2 activates the carboxy group and protects the α-amino group of amino acids. The corresponding amino acid amides were synthesized in good yields without racemization.
T. Nobuta, H. Morishita, Y. Suto, N. Yamagiwa, Synlett, 2022, 33, 1563-1569.

HSi[OCH(CF3)2]3 catalyzes a reliable protocol for peptide bond formation in high yield that is generally applicable to natural and unnatural α-amino acids, β-amino acids, and peptides bearing various functional groups. This method facilitates the sustainable utilization of natural resources by using a catalyst and an auxiliary based on earth-abundant silicon.
W. Muramatsu, H. Yamamoto, Org. Lett., 2022, 24, 7194-7199.

Imidazolylsilanes are highly useful coupling reagents for peptide synthesis from N-,C-terminal unprotected amino acids with amino acid tert-butyl esters. An optional deprotection of the tert-butyl ester at the C-terminus and cyclization sequentially proceed to afford silacyclic dipeptides, that can act as both nucleophiles and electrophiles for further peptide elongation.
T. Hattori, H. Yamamoto, J. Am. Chem. Soc., 2022, 144, 1758-1765.

Thionyl fluoride (SOF2) is a powerful reagent for both the rapid syntheses of acyl fluorides and for one-pot syntheses of amides, peptides, esters, and thioesters. In addition, thionyl fluoride-mediated one-pot reactions can be extended beyond nucleophilic acyl substitutions to mild reductions of carboxylic acids using NaBH4.
T. G. Bolduc, C. Lee, W. P. Chappell, G. M. Sammis, J. Org. Chem., 2022, 87, 7308-7318.

The use two different silylating reagents (HSi[OCH(CF3)2]3, MTBSTFA) in the presence of CsF and imidazole as catalysts enables a one-pot peptide bond-forming reaction via activation and transient masking at C-termini and N-termini, respectively. This versatile method tolerates various side chains, while providing excellent yields without any racemization or polymerization.
W. Muramatsu, H. Yamamoto, J. Am. Chem. Soc., 2021, 143, 6792-6797.

A mild, tantalum-catalyzed solvent-free approach for the construction of amide bonds in the presence of 1-(trimethylsilyl)imidazole provides peptides in high yields without any epimerization.
W. Muramatsu, H. Yamamoto, J. Am. Chem. Soc., 2019, 141, 18926-18931.

In the presence of the Oxyma derivative 2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate, short peptides to oligopeptides could be synthesized by using EDCI and NaHCO3 in water without measurable racemization. Significantly, a simple basic and acidic aqueous workup procedure can remove all reagents utilized in the reactions to afford only coupling products in consistently excellent yields.
Q. Wang, Y. Wang, M. Kurosu, Org. Lett., 2012, 14, 3372-3375.

Mechanochemical coupling of peptide fragments containing highly epimerization-prone and/or highly hindered amino acids at C-term provided peptides in high yields and very low epimerization. Ball milling was clearly identified as the key element to obtain such results.
Y. Yeboue, M. Jean, G. Subra, J. Martinez, F. Lamaty, T.-X. Métro, Org. Lett., 2021, 23, 631-635.

Borane-tetrahydrofuran complex or borane-methyl sulfide complex is used to generate triacyloxyboranes, which can be effectively reacted with various nucleophiles (alkylamines, arylamines, hydrazides, alcohols, phenols) at reflux in toluene to provide the corresponding amides and esters in excellent yield.
Z. Huang, J. R. Reilly, R. N. Buckle, Synlett, 2007, 1026-1030.

The commercially available B(OCH2CF3)3 is as an effective reagent for the direct amidation of a variety of carboxylic acids with a broad range of amines. In most cases, products can be purified by a simple filtration using commercially available resins, with no need for aqueous workup or chromatography. The amidation of N-protected amino acids with both primary and secondary amines proceeds effectively, with very low levels of racemization.
R. M. Lanigan, P. Starkov, T. D. Sheppard, J. Org. Chem., 2013, 78, 4512-4523.

Carboxylic acids are converted into amides in moderate to high yields in the presence of a stoichiometric amount of trimethylaluminium and amines in toluene at 90˚C after 1 hour.
S. Chung, D. P. Uccello, H. Choi, J. I. Montgomery, J. Chen, Synlett, 2011, 2072-2074.

A method for the preparation of N-acylpyrroles involves condensation of carboxylic acids with 2,4,4-trimethoxybutan-1-amine, followed by acid-mediated cyclization to form the pyrrole ring. The preparative procedure is highly tolerant of various functional groups.
T. Maehara, R. Kanno, S. Yokoshima, T. Fukuyama, Org. Lett., 2012, 14, 1946-1948.

The conversion of carboxylic acids to their corresponding acid chlorides occurs rapidly in the presence of a tertiary amine base and 3,3-dichlorocyclopropenes via aromatic cation-activated nucleophilic acyl substitution. The effect of cyclopropene substituents on the rate of conversion is examined. Conditions were developed for the preparation of acid sensitive acid chlorides.
D. J. Hardee, L. Kovalchuke, T. H. Lambert, J. Am. Chem. Soc., 2010, 132, 5002-5003.

A general, mild, and highly chemoselective method for transamidation of unactivated tertiary amides by a direct acyl N-C bond cleavage with non-nucleophilic amines is performed in the absence of transition metals and operates under unusually mild reaction conditions. A direct amidation of abundant alkyl esters affords amide bonds with exquisite selectivity by acyl C-O bond cleavage.
G. Li, C.-L. Ji, X. Hong, M. Szostak, J. Am. Chem. Soc., 2019, 141, 11161-11172.

Lanthanum trifluoromethanesulfonate is an effective catalyst for the coupling of esters with amides to yield amides under mild conditions.
H. Morimoto, R. Fujiwara, Y. Shimizu, K. Morisaki, T. Ohshima, Org. Lett., 2014, 16, 2018-2021.

Aliphatic and/or aromatic esters were converted into the corresponding amides under mild conditions in good to excellent yields in the presence of tert-butoxide, water and air. The reaction is highly efficient, rapid, versatile, green and economical, and could find great practical application in organic synthesis, biochemistry, and industrial chemistry.
B. R. Kim, H.-G. Lee, S.-B. Kang, G. H. Sung, J.-J. Kim, J. K. Park, S.-G. Lee, Y.-J. Yoon, Synthesis, 2012, 44, 42-50.

The use of magnesium nitride as a convenient source of ammonia allows a direct transformation of esters to primary amides. Methyl, ethyl, isopropyl, and tert-butyl esters are converted to the corresponding carboxamides in good yields.
G. E. Veitch, K. L. Bridgwood, S. V. Ley, Org. Lett., 2008, 10, 3623-3625.

Copper sulfate mediates a highly selective, mild, and rapid N-acylation of various aliphatic and aromatic amines using thioacids in methanol at neutral conditions. All N-acylated products of primary and secondary amines were isolated in good yields. This method offers a simple workup, high yields, and is is not sensitive to other functional groups such as phenols, alcohols, and thiols.
S. M. Mali, R. D. Bhaisare, H. N. Gopi, J. Org. Chem., 2013, 78, 5550-5555.

A recently discovered precatalyst enables Pd-catalyzed Suzuki-Miyaura and Buchwald-Hartwig reactions involving cleavage of a C(acyl)-O bond of aryl esters as electrophiles under mild conditions. The Pd(II) precatalyst is highly active due to its fast reduction to a Pd(0) active species.
A. H. Dardir, P. R. Melvin, R. M. Davis, N. Hazari, M. M. Beromi, J. Org. Chem., 2018, 83, 469-477.

Formation of unstable but reactive acyl nitroso intermediates from Nα-protected hydroxamic acids in the presence of iodine and DMSO enables an efficient and straightforward coupling with an amino component to yield dipeptide esters.
M. Krishnamurthy, T. M. Vishwanatha, N. R. Panguluri, V. Panduranga, V. V. Sureshbabu, Synlett, 2015, 26, 2565-2569.

An iodine-NH3 • H2O system enables a direct transformation of aryl, heteroaryl, vinyl, or ethynyl methyl ketones or carbinols to the corresponding primary amides in good yields in aqueous media. A tandem Lieben-Haller-Bauer reaction mechanism is proposed.
L. Cao, J. Ding, M. Gao, Z. Wang, J. Li, A. Wu, Org. Lett., 2009, 11, 3810-3813.

ZrOCl2 • 8 H2O is a highly effective, water-tolerant, and reusable catalyst for the direct condensation of carboxylic acids and N,N′-dimethylurea under microwave irradiation to give the corresponding N-methylamides in moderate to excellent yields. ZrOCl2 • 8 H2O is a useful green catalyst due to its low toxicity, easy availability, low cost, ease of handling, easy recovery, good activity, and reusability.
D. Talukdar, L. Saikia, A. J. Thakur, Synlett, 2011, 1597-1601.

A general and efficient method enables the synthesis of tertiary amides from readily available tertiary amines and anhydrides in the presence of FeCl2 as catalyst and tert-butyl hydroperoxide in water (T-Hydro) as oxidant. Mechanistic studies indicated that the in situ-generated α-amino peroxide of tertiary amine and iminium ion act as key intermediates.
Y. Li, L. Ma, F. Jia, Z. Li, J. Org. Chem., 2013, 78, 5638-5646.

A novel oxygen-centered radical addition between acyl peroxides and isocyanides has been developed. A diverse collection of valuable arylcarboxyamides were easily synthesized by this protocol. From the preliminary mechanistic study, the elimination of carbon dioxide affords the product via an intramolecular rearrangement.
M. Chen, Y. Li, H. Tang, H. Ding, K. Wang, L. Yang, C. Li, M. Gao, A. Lei, Org. Lett., 2017, 19, 3147-3150.

The reaction of tert-butyl peroxybenzoate (TBPB) and ammonia/amines provides the corresponding primary, secondary, and tertiary amides under catalyst- and solvent-free conditions in excellent yields. TBPB is an efficient and highly chemoselective benzoylating reagent for aliphatic amines in the presence of aromatic amines and hydroxyl groups.
D. K. T. Yadav, B. M. Bhanage, Synlett, 2015, 26, 1862-1866.

A Co-catalyzed oxidant-free reaction of carboxylic acids with organic azides in the presence of tert-butyl isocyanide enables an effective synthesis of N-sulfonylcarboxamides in very good yields. The protocol offers short times, low temperatures, and broad substrate scope.
Y. Fang, Z.-Y. Gu, S.-Y. Wang, J.-M. Yang, S.-J. Ji, J. Org. Chem., 2018, 83, 9364-9369.

N-Cbz-protected amino acids reacted with various aryl amines in the presence of methanesulfonyl chloride and N-methylimidazole in dichloromethane to give the corresponding arylamides in high yields without racemization under these mild conditions.
L. Mao, Z. Wang, Y. Li, X. Han, W. Zhou, Synlett, 2011, 129-133.

1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) catalyzes the amidation of acyl imidazoles. The rate acceleration is especially evident with traditionally unreactive, electron-deficient anilines. DBU offers safety and cost advantages over more commonly employed catalysts such as 1-hydroxybenzotriazole (HOBt).
C. Larrive-Aboussafy, B. P. Jones, K. E. Price, M. A. Hardink, R. W. McLaughlin, B. M. Lillie, J. M. Hawkins, R. Vaidyanathan, Org. Lett., 2010, 12, 324-327.

Malonic acid derivatives undergo unusually mild decarboxylation in the presence of N,N′-carbonyldiimidazole (CDI) at room temperature to generate a carbonyl imidazole intermediate in high yield. Subsequent reactions with various nucleophiles in an efficient one-pot process leads to amides, esters or carboxylic acids.
D. Lafrance, P. Bowles, K. Leeman, R. Rafka, Org. Lett., 2011, 13, 2322-2325.

Deprotonated 1,2,4-triazole is an active acyl transfer catalyst suitable for the aminolysis and transesterification of esters.
X. Yang, V. B. Birman, Org. Lett., 2009, 11, 1499-1502.

Amines are efficiently acylated by both cyclic and acyclic anhydrides in aqueous medium with sodium dodecyl sulfate (SDS) - without use of acidic or basic reagents. Various amines and anhydrides were reacted with equal ease. Chemoselective acylation in the presence of phenols and thiols has been achieved. No chromatographic separation is required for isolation of the acylated products.
S. Naik, G. Bhattacharjya, B. Talukdar, B. K. Patel, Eur. J. Org. Chem., 2004, 1254-1260.

Various alcohols, thiols, phenols, and amines can be acetylated using acetic anhydride in the presence of catalytic quantity of silver triflate. The method proceeds under mild conditions, does not involve cumbersome workup, and the resulting products are obtained in high yields within a reasonable time.
R. Das, D. Chakraborty, Synthesis, 2011, 1621-1625.

Phosphomolybdic acid (PMA) is a simple and efficient catalyst for the acetylation of structurally diverse alcohols, phenols, and amines. Acetylation reactions with acetic anhydride proceed in excellent yield in the presence of a catalytic amount of PMA at ambient temperature within a relatively short reaction time under solvent-free conditions.
S. T. Kadam, S. S. Kim, Synthesis, 2008, 267-268.

Copper(II) tetrafluoroborate efficiently catalyzes acetylation of structurally diverse phenols, alcohols, thiols, and amines with stoichiometric amounts of Ac2O under solvent-free conditions at room temperature. Acid-sensitive alcohols are smoothly acetylated without competitive side reactions.
A. K. Chakraborti, R. Gulhane, Shivani, Synthesis, 2004, 111-115.

Multivalent metal salts, such as ferric chloride and sulfate, are active and versatile catalysts for the amidation of aliphatic fatty acids with long-chain aliphatic amines.
Y. Terada, N. Ieda, K. Komura, Y. Sugi, Synthesis, 2008, 2318-2319.

Aliphatic, aromatic, and heteroaromatic carboxylic acids in the form of their salts condense with aryl isocyanates at room temperature with loss of carbon dioxide to give the corresponding amides in high yield. Application of the reaction to acyl isocyanates gives unsymmetric imides. The reaction is compatible with hydroxyl groups and both Fmoc and Boc protecting groups for amines.
K. Sasaki, D. Crich, Org. Lett., 2011, 13, 2256-2259.

2,2′-Dipyridyl diselenide catalyzes a direct reaction of carboxylic acids with azides and trimethylphosphine at room temperature. The mechanism of the process, which is not an aza-Wittig reaction, has been elucidated.
J. Burés, M. Martín, F. Urpí, J. Vilarrasa, J. Org. Chem., 2009, 74, 2203-2206.

The Staudinger ligation can be used to couple a peptide with a C-terminal phosphinothioester to another with an N-terminal α-azido group to form a single peptide that contains no residual atoms.
B. L. Nilsson, L. L. Kiessling, R. T. Raines, Org. Lett., 2001, 3, 9-12.

2-Acyl-4,5-dichloropyridazin-3-ones served as stable, convenient and chemoselective N-acylating reagents for amines under neutral conditions.
Y.-J. Kang, H.-A Chung, J.-J. Kim, Y.-J. Yoon, Synthesis, 2002, 733-738.

A straightforward trimethylsilylation protocol activates a thiol acid for peptide bond formation at neutral pH using bistrimethylsilylacetamide (BSA). A unique reactivity of the generated O-silylthionoesters toward amines provides oxoamides.
W. Wu, Z. Zhang, L. S. Liebeskind, J. Am. Chem. Soc., 2011, 133, 14256-14259.

A novel amide bond formation strategy from simple thioacid and amine starting materials is mediated by unstable but very reactive S-nitrosothioacid intermediates. This fast reaction under mild conditions should be useful in synthesis.
J. Pan, N. O. Devarie-Baez, M. Xian, Org. Lett., 2011, 13, 1092-1094.

Thio FCMA intermediates, generated from the reactions of thioacids with isonitriles, are active acyl donors, that form amide bonds under neutral conditions.
Y. Rao, X. Li, S. J. Danishefsky, J. Am. Chem. Soc., 2009, 131, 12924-12926.

Thioacids derived from N-protected amino or polypeptide acids undergo facile N-acylation with aromatic amines to afford aryl amides in good to excellent yields and enantiopurities in the presence of iodine, 1-hydroxybenzotriazole and N,N-diisopropylethylamine at room temperature. This oxidative Nα-acylation also furnishes difficult-to-prepare N-Fmoc amino acid 4-nitroanilides in good yields.
C. Madhu, T. M. Vishwanatha, V. V. Sureshbabu, Synthesis, 2013, 45, 2727-2736.

Microwave reactions of primary and secondary amines with imidoylbenzotriazoles gave various polysubstituted amidines in good yields. Convenient preparations of a variety of amides and imidoylbenzotriazoles have also been developed using microwave irradiation under mild conditions and short reaction times.
A. R. Katritzky, C. Cai, S. K. Singh, J. Org. Chem., 2006, 71, 3375-3380.

Various alcohols, phenols, amines and thiols may easily be converted into acetate derivatives by treatment with acetic anhydride in the presence of acetonyltriphenylphosphonium bromide in good yields at room temperature. With the same precatalyst, both aliphatic and aromatic aldehydes can be transformed into the corresponding gem-diacetates under reflux conditions.
A. T. Khan, L. H. Choudry, S. Ghosh, Eur. J. Org. Chem., 2005, 2782-2787.

Acyl halide-methanol mixtures are efficient reagents for the one-pot transformation of t-butyl carbamates into amides. This transformation can be carried out in the presence of a benzyloxycarbonyl group.
A. Nazih, D. Heissler, Synthesis, 2002, 203-206.

An efficient dynamic kinetic resolution of amines combines a ruthenium-catalyzed racemization with a lipase-catalyzed resolution. A variety of primary amines were transformed into one enantiomer of the amide in high yield and high enantioselectivity.
J. Paetzold, J. E. Bäckvall, J. Am. Chem. Soc., 2005, 127, 17620-17621.

A practical procedure for an efficient dynamic kinetic resolution of primary amines employs a palladium nanocatalyst as racemization catalyst, a commercial lipase as resolution catalyst, and ethyl acetate or ethyl methoxyacetate as acyl donor. Various amines and one amino acid amide have been resolved with good yields and high enantiomeric excesses.
M.-J. Kim, W.-H. Kim, K. Han, Y. K. Choi, J. Park, Org. Lett., 2007, 9, 1157-1159.

A practical procedure for an efficient dynamic kinetic resolution of primary amines employs a palladium nanocatalyst as racemization catalyst, a commercial lipase as resolution catalyst, and ethyl acetate or ethyl methoxyacetate as acyl donor. Various amines and one amino acid amide have been resolved with good yields and high enantiomeric excesses.
M.-J. Kim, W.-H. Kim, K. Han, Y. K. Choi, J. Park, Org. Lett., 2007, 9, 1157-1159.

A mild, versatile, copper-catalyzed three-component coupling of organoindium reagents with imines and acid chlorides provides α-substituted amides or N-protected amines in a single step with the sole byproduct being indium trichloride.
D. A. Black, B. A. Arndtsen, Org. Lett., 2006, 8, 1991-1993.

A simple, practical, and catalytic method for the N-formylation in the presence of molecular iodine as a catalyst under solvent-free conditions is applicable to a wide variety of amines. α-Amino acid esters can be converted without epimerization.
J.-G. Kim, D. O. Jang, Synlett, 2010, 2093-2096.

A simple, mild method for N-formylation in the presence of indium metal as a catalyst under solvent-free conditions is applicable to the chemoselective reaction of amines and α-amino acid esters without epimerization.
J.-G. Kima, D. O. Jang, Synlett, 2010, 1231-1234.

Formyloxyacetoxyphenylmethane is a stable, water-tolerant, N-formylating reagent that can be used under mild, solvent-free conditions for the preparation of a range of N-formamides, N-formylanilines, N-formyl-α-amino acids, N-formylpeptides, and isocyanides.
R. S. L. Chapman, R. Lawrence, J. M. J. Williams, S. D. Bull, Org. Lett., 2017, 19, 4908-4911.

A mild, simple, and selective N-formylation of amines with formic acid in the presence of ZnO under solvent-free conditions gives products in excellent yields.
M. Hosseini-Sarvari, H. Sharghi, J. Org. Chem., 2006, 71, 6652-6654.

Various tertiary benzanilide derivatives were effectively synthesized in high yields from a broad range substituted benzoic acid and N-monoalkylated anilines using dichlorotriphenylphosphorane in chloroform. Allyl, Boc, MPM and the Z group were unaffected under these conditions.
I. Azumaya, T. Okamoto, F. Imabeppu, H. Takayanagi, Tetrahedron, 2003, 59, 2325-2331.

In the presence of sodium acetate, the reaction between 2,2,6-trimethyl-4H-1,3-dioxin-4-one and secondary or tertiary alcohols or primary or secondary amines could be carried out in refluxing tetrahydrofuran. Under these much milder conditions, side products were avoided, and β-keto esters and β-ketoamides were normally obtained in quantitative yields.
V. Sridharan, M. Ruiz, J. C. Menéndez, Synthesis, 2010, 1053-1057.

An amidation of unactivated esters with amino alcohols catalazyed by a stable nitrogen-heterocyclic carbene is described. The mechanism is discussed.
M. Movassaghi, M. A. Schmidt, Org. Lett., 2005, 7, 2373-2376.

A direct enantioselective copper hydride (CuH)-catalyzed synthesis of β-chiral amides from α,β-unsaturated carboxylic acids and secondary amines under mild reaction conditions tolerates a variety of functional groups in the β-position including several heteroarenes. A subsequent iridium-catalyzed reduction to γ-chiral amines can be performed in the same flask.
A. Link, Y. Zhou, S. L. Buchwald, Org. Lett., 2020, 22, 5666-5670.

LiNTf2 is able to activate cyclic esters towards ring opening with a stoichiometric amount of amines, thus leading to clean open-chain amides under mild conditions. The generality of the method was demonstrated by a range of selected lactones and amines.
C. Lalli, A. Trabocchi, G. Menchi, A. Guarna, Synlett, 2008, 189-192.

A small library of α,β-unsaturated oxindoles was prepared by an efficient microwave-assisted one-pot sequence comprising an aromatic substitution followed by an ionic Horner-Wadsworth-Emmons olefination.
A. Teichert, K. Jantos, K. Harms, A. Studer, Org. Lett., 2004, 6, 3477-3480.

Various alcohols, amines and N-hydroxylamines gave corresponding formylated adducts in high yields by treatment with 2,2,2-trifluoroethyl formate (TFEF). Chemoselective formylation of a primary amine could be readily achieved in the presence of an unprotected primary alcohol.
D. R. Hill, C.-N. Hsiao, R. Kurukulasuriya, S. Wittenberger, Org. Lett., 2002, 4, 111-113.

Deoxo-Fluor is a versatile and mild reagent for acyl fluoride generation and subsequent one-flask amide coupling. The conversion of acids to amides and Weinreb amides and the use of Deoxo-Fluor as peptide-coupling reagent have been explored. Products were isolated after facile purification in good yields.
J. M. White, A. R. Tunoori, B. J. Turunen, G. I. Georg, J. Org. Chem., 2004, 69, 2573-2576.

A stereoconservative protection and deprotection method of amino and carboxyl groups includes the generation of N-Phthaloyl N'-alkyl secondary amides from N-phthaloyl amino acids by using a mixed anhydride method. These secondary amides have been transformed by thermal rearrangement of the intermediate nitrosoamides to esters with retention of configuration and excellent yields.
D. M. Shendage, R. Froehlich, G. Haufe, Org. Lett., 2004, 6, 3675-3678.

Preparation of One-Carbon Homologated Amides from Aldehydes or Primary Alcohols
M. K. Gupta, Z. Li, T. S. Snowden, Org. Lett., 2014, 16, 1602-1605.

Formation of N-alkenyl alkynylamides by N-acylation of imines with alkynoyl chlorides and the subsequent cationic Au(I)/PPh3-catalyzed cycloisomerization allows a convergent and rapid assembly of substituted 2-pyridones.
H. Imase, K. Noguchi, M. Hirano, K. Tanaka, Org. Lett., 2008, 10, 3563-3566.

In the presence of trichloroisocyanuric acid, triphenylphosphine, and sodium cyanamide, readily available carboxylic acids were converted into N-acylcyanamides in good to excellent yields within some minutes at room temperature under ultrasound irradiation. In addition, N-acyl-substituted imidazolones were readily accessible through guanylation-cyclization of in situ generated N-acylcyanamides.
W. Phakhodee, D. Yamano, M. Pattarawarapan, Synlett, 2020, 31, 703-707.

Ynamides as coupling reagents enable a practical one-pot strategy for α-keto amide bond formation under extremely mild reaction conditions. Diversely structural α-ketoamides were afforded in very good yields. This reaction offers wide functional group tolerance and has potential applications in synthetic and medicinal chemistry.
J. Ma, X. Cui, J. Xu, Y. Tan, Y. Wang, X. Wang, Y. Li, J. Org. Chem., 2022, 87, 3661-3667.

An amination reaction of in situ generated gem-difluoro-enolates with nitrosoarenes furnished α-ketoamides in very high yields. This nitroso aldol reaction is very fast (typically completed within 5 min) and scalable and tolerates various sensitive functional groups. Amination with azodicarboxylates smoothly produced fluorinated α-amino ketones.
M. K. Reddy, I. Ramakrishna, M. Baidya, Org. Lett., 2018, 20, 4579-4583.

A simple and efficient oxidative coupling of diazoesters and α-diazoketones with NH4I provides primary oxamates and α-ketoamides in good yields. This metal-free protocol is performed under mild conditions and has a wide substrate scope.
H. Wang, Y. Zhao, Y. Zheng, S. Fang, J. Li, X. Wan, J. Org. Chem., 2020, 85, 3050-3058.

The reaction of sulfoxonium ylides with primary or secondary amines afforded α-ketothioamides in the presence of elemental sulfur, whereas α-ketoamides were produced when I2 and TBHP were present. This simple, scalable reaction proceeded well at room temperature, tolerated a range of functional group, and generated the corresponding products in very good yields.
T. N. Chaubey, P. J. Borpatra, A. Sharma, S. K. Pandey, Org. Lett., 2022, 24, 8062-8066.