Categories: C-N Bond Formation >
Synthesis of sulfonamides
[(p-cymene)Ru(2,2'-bpyO)(H2O)] is a general and efficient catalyst for the N-methylation of amines and sulfonamides with methanol in the presence of a carbonate salt. The reaction tolerates a series of sensitive substituents, such as nitro, ester, cyano, and vinyl groups.
P. Liu, N. T. Tung, X. Xu, J. Yang, F. Li, J. Org. Chem., 2021, 86, 2621-2631.
A water-soluble metal-ligand bifunctional dinuclear iridium complex catalyzes an N-methylation of amines with methanol in aqueous solution. A range of desirable products were obtained in high yields under environmentally benign conditions.
C. Meng, P. Liu, N. T. Tung, X. Han, F. Li, J. Org. Chem., 2020, 85, 5815-5824.
Using 0.5 mol % [Ru(p-cymene)Cl2]2 with the bidentate phosphines dppf or DPEphos as the catalyst, primary amines have been converted into secondary amines, and secondary amines into tertiary amines. N-Heterocyclization reactions of primary amines have been achieved, as well as alkylation reactions of primary sulfonamides.
M. H. S. A. Hamid, C. L. Allen, G. W. Lamb, A. C. Maxwell, H. C. Maytum, A. J. A. Watson, J. M. J. Williams, J. Am. Chem. Soc., 2009, 131, 1766-1774.
A borrowing hydrogen approach using a well-defined and bench-stable Mn(I) PNP pincer precatalyst enables an efficient manganese-catalyzed N-alkylation of sulfonamides with benzylic and simple primary aliphatic alcohols as alkylating agents. A diverse range of aryl and alkyl sulfonamides undergoes mono-N-alkylation in excellent yields.
B. G. Reed-Berendt, L. C. Morrill, J. Org. Chem., 2019, 84, 3715-3724.
A catalytic amount of manganese dioxide and solvent-free conditions under air enabled a practical and efficient N-alkylation method for a variety of sulfonamides and amines using alcohols as green alkylating reagents.
X. Yu, C. Liu, L. Jiang, Q. Xu, Org. Lett., 2011, 13, 6184-6187.
Halogen bonding induces an intermolecular Csp3-H amination and even enables a hydrogen atom transfer relay strategy to access privileged pyrrolidine structures directly from alkanes. Mechanistic studies support the presence of multiple halogen bond interactions.
F. Wu, J. P. Ariyarathna, N. Kaur, N.-E. Alom, M. L. Kennell, O. H. Bassiouni, W. Li, Org. Lett., 2020, 22, 2135-2140.
Microwave heating enables a Borrowing Hydrogen strategy to form C-N bonds from alcohols and amines, removes the need for solvent and reduces the reaction times, while the results are comparable with those using thermal heating.
A. J. A. Watson, A. C. Maxwell, J. M. J. Williams, J. Org. Chem., 2011, 76, 2328-2331.
A base-catalyzed/promoted transition-metal-free direct alkylation of amines with either aromatic or aliphatic alcohols provides the desired amines in good yields.
Q.-Q. Li, Z.-F. Xiao, C.-Z. Yao, H.-X. Zheng, Y.-B. Kang, Org. Lett., 2015, 17, 5328-5331.
A catalyst-free Petasis reaction of sulfonamides as amine components, glyoxylic acid, and aryl- or alkenylboronic acids tolerates a broad range of functional groups and provides a wide array of α-amino acid derivatives.
A. M. Diehl, O. Ouadoudi, E. Andreadou, G. Manolikakes, Synthesis, 2018, 50, 3936-3946.
A palladium-catalyzed three-component synthesis of arylmethylsulfonamide derivatives from sulfonamides, paraformaldehyde, and arylboronic acids is operationally simple and provides a broad range of structurally interesting sulfonamidomethyl compounds.
T. Beisel, G. Manolikakes, Synthesis, 2016, 48, 379-386.
An intermolecular alkylation of sulfonamides with trichloroacetimidates occurs in refluxing toluene without additives. Unsubstituted sulfonamides provide better yields than more encumbered N-alkyl sulfonamides, whereas the trichloroacetimidate alkylating agent must be a stable cation precursor.
D. R. Wallach, J. D. Chisholm, J. Org. Chem., 2016, 81, 8035-8042.
A convenient, general, and high yielding Pd-catalyzed cross-coupling of methanesulfonamide with aryl bromides and chlorides eliminates concern over genotoxic impurities that can arise when an aniline is reacted with methanesulfonyl chloride. The application of this method to the synthesis of dofetilide is also reported.
B. R. Rosen, J. C. Ruble, T. J. Beauchamp, A. Navarro, Org. Lett., 2011, 13, 2564-2567.
A biaryl phosphine ligand, t-BuXPhos and K3PO4 in tert-amyl alcohol was found to be the optimal base-solvent combination for a Pd-catalyzed sulfonamidation of aryl nonafluorobutanesulfonates. The reaction conditions were tolerant of various functional groups. The only identified limitation of this methodology is the inability of 2,6-disubstituted aryl nonaflates to efficiently participate in the reaction.
S. Shekhar, T. B. Dunn, B. J. Kotecki, D. K. Montavon, S. C. Cullen, J. Org. Chem., 2011, 76, 4552-4553.
A mild and efficient method for the synthesis of N-arylsulfonamides in the presence of CuCl as catalyst proceeds readily at room temperature in an open flask using a variety of sulfonyl azides and boronic acids without any base, ligand, or additive.
S.-Y. Moon, J. Nam, K. Rathwell, W.-S. Kim, Org. Lett., 2014, 16, 338-339.
An efficient method for the copper-catalyzed arylation of sulfonamides in water under ligand-free conditions offers high yields, simple workup procedure, and elimination of toxic materials.
M. Nasrollahzadeh, A. Ehsani, M. Maham, Synlett, 2014, 25, 505-508.
The arylation of N-H and O-H containing compounds at room temperature with phenylboronic acids is promoted in the presence of cupric acetate and a tertiary amine. Substrates include phenols, amines, anilines, amides, imides, ureas, carbamates, and sulfonamides.
D. M. T. Chan, K. L. Monaco, R.-P. Wang, M. P. Winteres, Tetrahedron Lett., 1998, 39, 2933-2936.
A general and direct N-arylation of sulfonamides and NH-sulfoximines by sodium arylsulfinates through a desulfitative pathway proceeded with catalytic loadings of Cu(II) without any external ligands. This arylation protocol offers high efficiency and good substituent tolerance.
Y. Jiang, Y. You, W. Dong, Z. Peng, Y. Zhang, D. An, J. Org. Chem., 2017, 82, 5810-5818.
An efficient, mild and transition-metal-free N-arylation of amines, sulfonamides, and carbamates and O-arylation of phenols and carboxylic acids has been achieved by using various o-silylaryl triflates in the presence of CsF.
Z. Liu, R. C. Larock, J. Org. Chem., 2006, 71, 3198-3209.
Iridium-catalyzed direct ortho C-H amidation of arenes works well with sulfonyl- and aryl azides as the nitrogen source. The reaction proceeds efficiently with a broad range of conventional directing groups with excellent functional group compatibility under mild conditions via 5- as well as 6-membered iridacycle intermediates.
D. Lee, Y. Kim, S. Chan, J. Org. Chem., 2013, 78, 11102-11109.
A metal-free allylic amination of alkenes with simple sulfonamides and sulfamates allows the introduction of a wide range of nitrogen functionality at the allylic position of alkenes with unique regioselectivity and no allylic transposition in the presence of phosphine selenides or selenoureas as catalysts.
W. P. Teh, D. C. Obenschain, B. M. Black, F. E. Michael, J. Am. Chem. Soc., 2020, 142, 16716-16722.
A Facile Highly Regio- and Stereoselective Preparation of N-Tosyl Allylic Amines from Allylic Alcohols and Tosyl Isocyanate via Palladium(II)-Catalyzed Aminopalladation-β-Heteroatom Elimination
A. Lei, X. Lu, Org. Lett., 2000, 2, 2357-2360.
An oxidative decarboxylation of β,γ-unsaturated carboxylic acids mediated by PhI(OAc)2 gives the corresponding allylic acetates. In addition, a decarboxylative C-N bond formation was achieved. Mechanistic studies suggest an unique reactivity of hypervalent iodine reagents in this ionic oxidative decarboxylation.
K. Kiyokawa, S. Yahata, T. Kojima, S. Minakata, Org. Lett., 2014, 16, 4646-4649.
A range of enol triflates can be coupled with amides, carbamates, and sulfonamides using palladium catalysis. This method allows the synthesis of enamides, which may not be readily available by other means.
D. J. Wallace, D. J. Klauber, C.-Y. Chen, R. P. Volante, Org. Lett., 2003, 5, 4749-4752.
Nucleophilic addition of sulfonamides to 1-bromo-1-alkynes provided (Z)-N-(1-bromo-1-alken-2-yl)-p-toluenesulfonamides in good yield and in a highly regio- and stereoselective manner. A subsequent reaction in the presence of a palladium catalyst under Heck conditions afforded substituted pyrroles in good yield.
M. Yamagishi, K. Nishigai, T. Hata, H. Urabe, Org. Lett., 2011, 13, 4873-4875.
Benzylic hydrocarbons are selectively converted to the corresponding sulfonamides by the [Cu(CH3CN)4]PF6-catalyzed reaction with anhydrous TolSO2NNaCl (chloramine-T). Under the same conditions, representative ethers and olefins are also amidated.
R. Bhuyan, K. M. Nicholas, Org. Lett., 2007, 9, 3957-3959.
A palladium-catalyzed, enantioselective three-component reaction of sulfonamides, aldehydes, and arylboronic acids generates a wide array of α-arylamines with high yields and enantioselectivities. Notably, this process tolerates air and moisture and provides an operationally simple approach for the synthesis of chiral α-arylamines.
T. Beisel, G. Manolikakes, Org. Lett., 2015, 17, 3162-3165.
A copper-catalyzed amidation of allylic and benzylic C-H is applicable to the coupling of a diverse set of hydrocarbon species with aryl, heteroaryl, and alkyl sulfonamides and is tolerant of a variety of functional groups.
G. Pelletier, D. A. Powell, Org. Lett., 2006, 8, 6031-6034.
A robust transition-metal-free reaction of sulfonamides and (Z)-1,2-dichloroalkenes or alkynyl chlorides enables the synthesis of internal and terminal ynamides. The reaction tolerates various functional groups.
X. Zeng, Y. Tu, Z. Zhang, C. You, J. Wu, Z. Ye, J. Zhao, J. Org. Chem., 2019, 84, 4458-4466.
A crystalline ethynyl-1,2-benziodoxol-3(1H)-one (EBX)-acetonitrile complex can be used for N-ethynylation of various sulfonamides under mild conditions.
M. Yudasaka, D. Shimbo, T. Maruyama, N. Tada, A. Itoh, Org. Lett., 2019, 21, 1098-1102.
A robust one-step synthesis of ynamides from vinyl dichlorides and electron deficient amides as cheap and easily available starting materials proceeds under mild reaction conditions in open air In the absence of a transition-metal catalyst. This strategy is not only suitable for the synthesis of both terminal and internal ynamides but also amenable for large-scale preparation.
Y. Tu, X. Zeng, H. Wang, J. Zhao, Org. Lett., 2018, 20, 280-283.
A single Cu(II) catalyst couples a diverse range of nitrogen sources with various alkynes and aldehydes without the addition of ligand or base. Copper-catalyzed alkynylation involving p-toluenesulfonamide provides high yields of N-Ts-protected propargylamines. The superior activity of copper(II) triflate also allows this three-component alkynylation to incorporate a ketone.
C. E. Meyet, C. J. Pierce, C. H. Larsen, Org. Lett., 2012, 14, 964-967.
An oxidative amination of allenes using a single hypervalent iodine reagent proceeds very efficiently for monosubstituted allenes and leads to formation of the corresponding propargylic amines, either as the internal or as the terminal amine depending on the addition of triphenylphosphine oxide to the iodine(III) reagent.
N. Purkait, S. Okumura, J. A. Souto, K. Muņiz, Org. Lett., 2014, 16, 4750-4753.
Acid chlorides can be activated to transient acid iodide intermediates using a simple iodide source. This indermediates undergo nucleophilic attack from a variety of relatively weak nucleophiles - including Friedel-Crafts acylation of N-methylpyrroles, N-acylation of sulfonamides, and acylation reactions of hindered phenol derivatives.
R. J. Wakeham, J. E. Taylor, S. D. Bull, J. A. Morris, J. M. J. Williams, Org. Lett., 2013, 15, 702-705.
The use of PhI=NTs/PhI=NNs as the nitrogen source in the presence of inexpensive iron(II) chloride + pyridine as the in situ formed precatalyst enables amidation of aldehydes under mild conditions at room temperature or microwave assisted conditions. The protocol is operationally straightforward and accomplished in good product yields and with complete chemoselectivity.
T. M. U. Ton, C. Tejo, S. Tania, J. W. W. Chang, P. W. H. Chan, J. Org. Chem., 2011, 76, 4894-4904.
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.
Dibenzenesulfonimide is a nitrogen source of choice in terms of the yields and the reaction time in a transition-metal-free intermolecular N-H insertion of α-diazocarbonyl compounds. Primary mechanistic experiments suggest that a pathway involves a sequence of protonation and nucleophilic substitution.
X. Luo, G. Chen, L. He, X. Huang, J. Org. Chem., 2016, 81, 2943-2949.
N-Sulfonyl ketenimine formation followed by a probable 1,3-OAc migration ([3,3]-sigmatropic rearrangement) enables a synthesis of trans-α,β-unsaturated N-tosylamides from readily accessible propargyl acetates and sulfonyl azides in the presence of CuI as catalyst. The reaction is very general and affords products at ambient temperature with excellent diastereoselectivity in good yields.
Y. K. Kumar, G. R. Kumar, M. S. Reddy, J. Org. Chem., 2014, 79, 823-828.
A combination of N-bromoimide and DBU enables allylic amination reactions of alkenes, in which both internal and external nitrogen nucleophiles can be installed directly. Dual activation of NBS or NBP by DBU leads to more electrophilic bromine and more nucleophilic nitrogen atoms simultaneously. This protocol provides a complementary access to allylic amination under mild conditions.
Y. Wei, F. Liang, X. Zhang, Org. Lett., 2013, 15, 5186-5189.
A gold(I)-catalyzed decarboxylative amination of allylic N-tosylcarbamates via base-induced aza-Claisen rearrangement in H2O allows the synthesis of substituted N-tosyl allylic amines in good yield, regioselectivity, and stereoselectivity. This transformation represents an efficient and environmentally benign protocol for the synthesis of N-tosyl allylic amines.
D. Xing, D. Yang, Org. Lett., 2010, 12, 1068-1071.
Orangoselenium catalysis enables an efficient route to 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of a base. In the absence of bases α,β-unsaturated aldehydes were formed in excellent yield. The hydroxy group is crucial for the direct amination.
Z. Deng, J. Wei, L. Liao, H. Huang, X. Zhao, Org. Lett., 2015, 17, 1834-1837.
A reaction between terminal alkynes and sulfonamides under ambient air using PIDA (diacetoxy iodobenzene) provides α-sulfonylamino ketones. This metal-free reaction offers a broad substrate scope, excellent regioselectivity, easily accessible reactants, and mild reaction conditions and is operationally simple.
S. Mahato, S. Santra, G. V. Zyryanov, A. Majee, J. Org. Chem., 2019, 84, 3176-3183.
An economic and practical transformation from secondary alkyl-substituted propargyl acetates to a variety of nucleophilic substitution products is catalyzed by inexpensive InCl3. High yields and excellent chemoselectivity were obtained. Five-, six-, and seven-membered propargyl cycloethers were also successfully constructed.
M. Lin, L. Hao, X.-t. Liu, Q.-z. Chen, F. Wu, P. Yan, S.-x. Xu, X.-l. Chen, J.-j. Wen, Z.-p. Zhan, Synlett, 2011, 665-670.
An efficient amidation reaction of saturated C-H bonds catalyzed by a unique disilver(I) complex is reported. The reaction is stereospecific and practical for the construction of amine-containing molecules.
Y. Cui, C. He, Angew. Chem. Int. Ed., 2004, 43, 4210-4212.
A highly efficient hydroamination of sulfonamides, carboxamides, and carbamates with unactivated olefins is catalyzed by an inexpensive zirconium salt under mild reaction conditions. The reactions gave good to excellent yields of the Markovnikov products.
L. Yang, L.-W. Xu, W. Zhou, Y.-H. Gao, W. Sun, C.-G. Xia, Synlett, 2009, 1167-1171.
A simple addition of phenols, carboxylic acids, and protected amines to olefins can be catalyzed by triflic acid. A low concentration of triflic acid and control of the reaction temperature help to tolerate functional groups, such as methoxyl substitution on aromatics.
Z. Li, J. Zhang, C. Brouwer, C.-G. Yang, N. W. Reich, C. He, Org. Lett., 2006, 8, 4175-4178.
Addition of sulfonamides to alkenes and conjugated dienes can be carried out using a low catalytic amount of (triphenyl phosphite)gold(I) chloride and silver triflate under thermal or microwave conditions and at r.t. in the case of dienes. Terminal alkenes undergo regioselective hydroamination at the internal carbon atom and dienes at the less substituted double bond.
X. Giner, C. Nájera, Org. Lett., 2008, 10, 2919-2922.
A general Pd-catalyzed, enantioselective three-component synthesis using readily available sulfonamides, glyoxylic acid derivatives, and boronic acids provides a broad range of α-arylglycines in high yields and excellent levels of enantioselectivity. Incorporation of Pbf-amides gives a racemization-free access to N-unprotected α-arylglycines.
T. Beisel, A. M. Diehl, G. Manolikakes, Org. Lett., 2016, 18, 4032-4035.
A combined amino- and N-heterocyclic carbene (NHC)-catalyzed one-pot reaction sequence using commercially available catalysts at low catalyst loadings gives β-hydroxy and β-amino esters in high yield and excellent enantiopurity. The generation of quaternary stereocenters and application in gram-scale synthesis were also realized, with no requirements of inert or anhydrous reaction conditions.
H. Jiang, B. Gschwend, Ł. Albrecht, K. A. Jørgensen, Org. Lett., 2010, 12, 5052-5055.
The use of iodosobenzene (PhIO) as oxidant and p-toluenesulfonamide (TsNH2) as aminating reagent in the presence of a catalytic amount of perchlorate zinc hexahydrate enables a direct α-amination of β-dicarbonyl compounds. The reaction proceeds quickly at rt to provide the corresponding α-N-tosylamido β-dicarbonyl compounds very good yields.
J. Yu, S.-S. Liu, J. Cui, X.-S. Hou, C. Zhang, Org. Lett., 2012, 14, 832-835.
In copper-catalyzed direct N-alkynylation, the use of pure and anhydrous K3PO4 provides higher ynamide yields in comparison to samples contaminated with hydrates (K3PO4 · 1.5 H2O and K3PO4 · 7 H2O). With high quality K3PO4, a number of ynamides were synthesized in good yields. In addition, ynamides can undergo regioselective hydroamination with carbamates.
K. Dooleweerd, H. Birkedal, T. Ruhland, T. Skrydstrup, J. Org. Chem., 2008, 73, 9447-9450.
A facile route to ynamides in high yields was achieved through an iron-catalyzed C-N coupling reaction of amides with alkynyl bromides in the presence of 20 mol % of N,N′-dimethylethane-1,2-diamine (DMEDA).
B. Yao, Z. Liang, T. Niu, Y. Zhang, J. Org. Chem., 2009, 74, 4630-4633.
A direct metal-free amination of arylalkynes with the hypervalent iodine reagent PhI(OAc)NTs2 provides rapid access to ynamides in an unprecedented intermolecular C-H to C-N bond conversion reaction. A related transformation between alkylated alkynes and the iodine(III) reagent gives cyclopentene amides.
J. A. Souto, P. Becker, A. Iglesias, K. Muņiz, J. Am. Chem. Soc., 2012, 134, 15505-15511.
An efficient intermolecular trans-selective β-hydroamidation of ynamides provides (Z)-ethene-1,2-diamide derivatives with excellent regio- and stereo-selectivities for a wide range of substrates. The reaction proceeds under basic conditions in the absence of a transition-metal catalyst.
Z. Peng, Z. Zhang, Y. Tu, X. Zeng, J. Zhao, Org. Lett., 2018, 20, 5688-5691.
Rhodium(II) azavinyl carbenes, which are conveniently generated from 1-sulfonyl-1,2,3-triazoles, undergo a facile, mild, and convergent formal 1,3-insertion into N-H and O-H bonds of primary and secondary amides, various alcohols, and carboxylic acids to afford a wide range of vicinally bisfunctionalized (Z)-olefins with perfect regio- and stereoselectivity.
S. Chuprakov, B. T. Worrell, N. Selander, R. K. Sit, V. V. Fokin, J. Am. Chem. Soc., 2014, 136, 195-202.
A catalyst- and metal-free visible-light-mediated protocol enables the iodoamination of miscellaneous olefins in high yields under environmentally benign reaction conditions using DMC as green and biodegradable solvent. Furthermore, the protocol allows for late-stage functionalization of bioactive molecules and can be scaled to gram quantities of product.
S. Engl, O. Reiser, Org. Lett., 2021, 23, 5581-5586.
A new procedure for aminobromination of olefins gives vicinal bromoamine derivatives in high yields using Cu, Mn, or V catalysts with p-toluenesulfonamide as nitrogen source and N-bromosuccinimide (NBS) as bromine source. Excellent regio- and stereoselectivity is shown for different olefinic substrates as well as transition metal catalysts.
V. V. Thakur, S. K. Talluri, A. Sudalai, Org. Lett., 2003, 5, 861-864.
A convenient and efficient iron-catalyzed aminobromination of alkenes has been developed using inexpensive FeCl2 as the catalyst, amides/sulfonamides and NBS as the nitrogen and bromine sources, respectively, under mild conditions.
Z. Wang, Y. Zhang, H. Fu, Y. Jiang, Y. Zhao, Synlett, 2008, 2667-2668.
In an efficient, catalyst-free, and metal-free bromoamidation of unactivated olefins, 4-(trifluoromethyl)benzenesulfonamide and N-bromosuccinimide were used as the nitrogen and halogen sources, respectively. The methodology is applicable to both cyclic and aliphatic olefins.
W. Z. Yu, F. Chen, Y. A. Cheng, Y.-Y. Yeung, J. Org. Chem., 2015, 80, 2815-2821.
An aminohalogenation of cinnamic esters with N,N-dichloro-p-toluenesulfonamide provides vicinal chloroamine derivatives in very good yields. The reaction was performed in MeCN using ZnCl2 or Cu(OTf)2 as catalyst. The stereochemistry was unambiguously determined by transforming one of the products to a known sample.
G. Li, H.-X. Wei, S. H. Kim, M. Neighbors, Org. Lett., 1999, 1, 395-397.
The direct oxidative N-acylation reaction of primary amides with aryl/α,β-unsaturated aldehydes was achieved in the presence of an azolium salt and an inorganic base using 3,3′,5,5′-tetra-tert-butyldiphenoquinone as the oxidant. The reaction provides an efficient approach for the synthesis of N-sulfonylcarboxamides, N-sulfinylcarboxamides, and dicarboxyimides in good yield.
C. Zheng, Y. Liu, C. Ma, J. Org. Chem., 2017, 82, 6940-6945.
A Rh(II)-catalyzed oxidative coupling of aldehydes and sulfonamides provides N-sulfonylcarboxamides in one step. Various sulfonamides were found to react with aromatic and aliphatic aldehydes to afford the desired products in very good yields.
J. Chan, K. D. Baucom, J. A. Murry, J. Am. Chem. Soc., 2007, 129, 14106-14107.
In a highly regioselective, direct visible-light-mediated aminofluorination of styrenes, a shelf-stable N-Ts-protected 1-aminopyridine salt serves as the nitrogen-radical precursor, and the commercially available hydrogen fluoride-pyridine was used as the nucleophilic fluoride source.
J.-N. Mo, W.-L. Yu, J.-Q. Chen, X.-Q. Hu, P.-F. Xu, Org. Lett., 2018, 20, 4471-4474.
In a copper-catalyzed intermolecular aminoalkynylation of alkenes, N-fluoro-N-alkylsulfonamides (NFASs) are used as nitrogen-centered radical precursors and alkynyltrimethoxysilanes as alkynylating reagents. This radical relay process presents an efficient and straightforward approach to various highly enantioenriched 2-alkynyl-2-arylethylamines in good yields.
Z. Hu, L. Fu, P. Chen, W. Cao, G. Liu, Org. Lett., 2021, 23, 107-112.
A series of vinyl sulfonamides was synthesized using the Horner reaction of aldehydes and diphenylphosphorylmethanesulfonamide. The sulfonamide reagent was easily prepared and can be stored indefinitely.
D. C. Reuter, J. E. McIntosh, A. C. Guinn, A. M. Madera, Synthesis, 2003, 2321-2324.
A Zn/CuI-mediated coupling of alkyl halides with vinyl sulfones, vinyl sulfonates, and vinyl sulfonamides is described. Formamide is a superior solvent for obtaining high yields.
M. M. Zhao, C. Qu, J. E. Lynch, J. Org. Chem., 2005, 70, 6944-6947.
Ynamides are moisture-sensitive and prone to hydration especially under acidic and heating conditions. An environmentally benign, robust Sonogashira coupling enables the synthesis of sulfonamide-based ynamides and arylynamines in water, using a readily available quaternary ammonium salt as the surfactant.
L. Zhao, H. Yang, R. Li, Y. Tao, X.-F. Guo, E. A. Anderson, A. Whiting, N. Wu, J. Org. Chem., 2021, 86, 1938-1947.
A copper-catalyzed coupling of Grignard or organozinc nucleophiles with chloroynamides, formed in situ from 1,2-dichloroenamides, provides a broad range of ynamides. The reaction is readily scaled and overcomes typical limitations in ynamide synthesis such as the use of ureas, carbamates, and bulky or aromatic amide derivatives.
S. J. Mansfield, R. C. Smith, J. R. J. Yong, O. L. Garry, E. A. Anderson, Org. Lett., 2019, 21, 2918-2922.