A simple and mild TEMPO-CuCl catalyzed aerobic oxidation of primary and secondary alcohols in ionic liquid [bmim][PF6] gave the corresponding aldehydes and ketones with no trace of overoxidation to carboxylic acids. The product can be isolated by a simple extraction with organic solvent, and the ionic liquid can be recycled or reused.
I. A. Ansari, R. Gree, Org. Lett., 2002, 4, 1507-1509.
A four-component system consisting of acetamido-TEMPO/Cu(ClO4)2/TMDP/DABCO in DMSO allows an efficient room-temperature aerobic alcohol oxidation of various alcohols into their corresponding aldehydes or ketones in good to excellent yields. The catalytic system can be recycled.
N. Jiang, A. J. Ragauskas, J. Org. Chem., 2006, 71, 7087-7090.
A highly efficient and practical Pd(II)/Cu(OAc)2 catalyzed Saegusa oxidation converts enol ethers to the corresponding enals at extremely low catalyst loadings under ligand-free and aqueous conditions. Its synthetic utility was demonstrated with a number of diverse substrates and large-scale applications.
Q. Zhu, Y. Luo, Y. Guo, Y. Zhang, Y. Tao, J. Org. Chem., 2021, 86, 5463-5476.
The system Cu(ClO4)2/acetamido-TEMPO/DMAP catalyses the room-temperature aerobic oxidation of primary alcohols to aldehydes in the ionic liquid [bmpy]PF6. The catalysts can be recycled and reused.
N. Jiang, A. J. Ragauskas, Org. Lett., 2005, 7, 3689-3692.
Ubiquitous carboxylic acids can serve as starting materials for a photocatalytic decarboxylative C-O bond formation reaction that provides rapid and facile access to the corresponding acetoxylated products.
S. Senaweera, K. C. Cartwrigt, J. A. Tunge, J. Org. Chem., 2019, 84, 12334-12343.
A direct metal-free α-hydroxylation of α-unsubstituted β-oxoesters and β-oxoamides using m-chloroperbenzoic acid as the oxidant enables straightforward metal-free access to important α-hydroxy-β-dicarbonyl moieties under mild reaction conditions. Furthermore, the hydroxylated products can readily be converted into vicinal tricarbonyl compounds, which are useful synthetic precursors.
H. Asahara, N. Nishiwaki, J. Org. Chem., 2014, 79, 11735-11739.
A Chan-Lam coupling reaction of benzylic and allylic boronic esters with primary and secondary anilines provides valuable alkyl amine products. Both secondary and tertiary boronic esters can be used as coupling partners, with mono-alkylation of the aniline occurring selectively.
J. D. Grayson, F. M. Dennis, C. C. Robertson, B. M. Partridge, J. Org. Chem., 2021, 86, 9883-9897.
A facile nickel-catalyzed oxidation of primary alcohols with tetrabutylammonium peroxydisulfate in the presence of ammonium hydrogen carbonate under basic aqueous conditions provides access to various aliphatic, aromatic and heterocyclic nitriles in excellent yields with very high purity.
F.-E. Chen, Y.-Y. Li, M. Xu, H.-Q. Jia, Synthesis, 2002, 1804-1806.
A general Pd-catalyzed oxidative aminocarbonylation of arylsilanes under mild conditions is promoted by a commercially available copper(II) fluoride, which acts as a dual silane activator and mild oxidant. The reaction is tolerant of a wide range of arylsilanes and various sensitive halide functional groups as well as a broad scope of amines.
J. Zhang, Y. Hou, Y. Ma, M. Szostak, J. Org. Chem., 2019, 84, 120-127.
A Mizoroki-Heck type reaction of boronic acids proceeds under a Pd(II)-mediated pathway using a catalytic amount of Pd(OAc)2 in the presence of Cu(OAc)2 as an oxidant. Treatment of a variety of alkenes with boronic acids, boronates, and sodium tetraphenylborate furnishes β-arylated and alkenylated products in very good yields.
X. Du, M. Suguro, K. Hirabayashi, A. Mori, T. Nishikata, N. Hagiwara, K. Kawata, T. Okeda, H. F. Wang, K. Fugami, M. Kosugi, Org. Lett., 2001, 3, 3313-3313.
An arylation/alkenylation of homoenolates from cyclopropanol precursors with boronic acids provides β-substituted enone and dienone derivatives in good yields. A simple ligand-free Pd(II) catalytic system is most efficient under open air conditions. The reaction tolerates a wide range of substrates and a variety of functional groups.
T. Ramar, M. A. M. Subbaiah, A. Ilangovan, J. Org. Chem., 2022, 87, 4508-4523.
A chelated Pd(II) complex catalyzes a coupling of organoborane reagents with cyclopropanol-derived β-ketone enolates to provide synthetically important β-aryl ketone intermediates in a chemoselective fashion.
T. Ramar, M. A. M. Subbaiah, A. Ilangovan, J. Org. Chem., 2020, 85, 7711-7727.
A carboxylic-acid-directed oxidative Heck reaction enables a direct synthesis of 4-aryl-3-butenoic acids in good yields.
S. Yang, L. Liu, Z. Zhou, Z. Huang, Y. Zhao, Org. Lett., 2021, 23, 296-299.
An enantioselective alkoxycarbonylation-amination cascade process of terminal allenes with CO, methanol, and arylamines proceeds under mild conditions (r.t., ambient pressure CO) via oxidative Pd(II) catalysis using a chiral aromatic spiroketal-based diphosphine ligand and a Cu(II) salt as an oxidant to afford various α-methylene-β-arylamino acid esters in good yields with excellent enantioselectivity and high regioselectivity.
J. Liu, Z. Han, X. Wang, Z. Wang, K. Ding, J. Am. Chem. Soc., 2015, 137, 15346-15349.
A Rh(III)-catalyzed β-C(sp2)-H arylation of various acyclic enamides with environmentally friendly arylsilanes offers extraordinary efficacy and stereoselectivity, a wide scope of substrates, and good functional group tolerance.
X. Jiang, G. Wang, Z. Zheng, X. Yu, Y. Hong, H. Xia, C. Yu, Org. Lett., 2021, 23, 31-36.
An oxidative cross-coupling reaction between activated olefins and vinyl boronate provides synthetically useful (E,E)-1,3-dienes. Exclusive stereoselectivity (only E,E-isomer) was achieved using base-free, ligand-free, and mild catalytic conditions with [RuCl2(p-cymene)]2 as catalyst.
D. H. Dethe, N. C. Beeralingappa, A. Uike, J. Org. Chem., 2021, 86, 3444-3455.
Metal-catalyzed vinylic C-H activation enables a chemodivergent cross-coupling of acrylamides and vinyl acetates. Depending on catalysts, selective olefinic C-H vinylation and alkenylation reactions efficiently generate a range of highly synthetically valuable butadienes with good functional group tolerance in good yields.
R. Logeswaran, M. Jeganmohan, Org. Lett., 2021, 23, 5679-5683.
A low-barrier photoinduced ligand to metal charge transfer (LMCT) enables a radical decarboxylative carbometalation strategy. Formation of a putative high-valent arylcopper(III) complex facilitates reductive eliminations to occur. This approach is suitable to address a previously unrealized general decarboxylative fluorination of benzoic acids at low temperature.
P. Xu, P. López-Rojas, T. Ritter, J. Am. Chem. Soc., 2021, 143, 5349-5354.
Ethyl bromodifluoroacetate as carbonyl source enables an efficient direct carbonation of aromatic acids to yield monoalkyl phthalate derivatives in good yields. A broad range of substrates bearing various functional groups were tolerated.
N. Tao, J. Wang, C. Yuan, R. Zeng, Y.-S. Zhao, Org. Lett., 2019, 21, 8607-8610.
A Pd(II)-catalyzed oxidative approach to construct polysubstituted pyrroles from N-homoallylicamines and arylboronic acids proceeds through cascade formation of C-C and C-N bonds via oxidative arylation of unactive alkenes, followed by intramolecular aza-Wacker cyclization.
J. Zheng, L. Huang, C. Huang, W. Wu, H. Jiang, J. Org. Chem., 2015, 80, 1235-1242.
A Pd-catalyzed annulation of enaminones and alkenes provides various NH-free pyrroles via activation of multiple C(sp2)-H bonds. The evolution of hydrogen has been confirmed by a hydrogen detector.
L. Fu, Y. Liu, J.-P. Wan, Org. Lett., 2021, 23, 4250-4255.
A Cu(OAc)2-promoted oxidation/[3+2]cycloaddition/aromatization cascade reaction provides tetrasubstituted NH-pyrroles in very good yields from a wide range of chalcones and diethyl iminodiacetates. This convenient methodology has several advantages, such as the use of easily accessible chalcones and readily available diethyl iminodiacetates, and mild reaction conditions.
Z.-q. Lin, C.-d. Li, Z.-c. Zhou, S. Xue, J.-r. Gao, Q. Ye, Y.-j. Li, Synlett, 2019, 30, 1442-1446.
A novel palladium-catalyzed oxidative, intramolecular cyclocarbonylation provides an efficient and direct approach for the construction of valuable 1,3,4-oxadiazole-2(3H)-ones and their derivatives.
F. Ji, X. Li, W. Guo, W. Wu, H. Jiang, J. Org. Chem., 2015, 80, 5713-5718.
Cp*Co(CO)I2 catalyzes a weakly coordinating, carbonyl-assisted C-H activation of aromatic systems with α,β-unsaturated ketone and subsequent aldol condensation to provode indenes under mild reaction conditions. The reaction shows excellent functional group compatibility.
D. H. Dethe, N. C B, A. A. Bhat, J. Org. Chem., 2020, 85, 7565-7575.
A palladium-catalyzed C-H carbonylation of benzylamines provides isoindolinone scaffolds in good yields under gas-free conditions by using benzene-1,3,5-triyl triformate (TFBen) as a convenient CO surrogate.
L-Y. Fu, J. Ying, X. Qi, J.-B. Peng, X.-F. Wu, J. Org. Chem., 2019, 84, 1238-1246.
A facile synthesis of hydrazides from N-tosylhydrazones under metal-free conditions was suitable for different substrates and tolerated various substituents. In a subsequent step, a series of indazolones could be prepared from corresponding o-bromobenzohydrazides under mild conditions.
S. Zhang, Q. Zhang, M. Tang, J. Org. Chem., 2022, 87, 3845-3850.
In a palladium-catalyzed oxidative carbonylation reaction for the synthesis of phthalimides, an imine and H2O, which are generated in situ from the condensation of aldehyde and amine, serve as self-sufficient directing group and nucleophile, respectively. This method provides rapid access to phthalimides starting from readily available materials with high atom- and step-economy in a one-pot manner.
F. Ji, J. Li, X. Li, W. Guo, W. Wu, H. Jiang, J. Org. Chem., 2018, 83, 104-112.
The use of Cu(OAc)2 enables a dehydrogenative cross-coupling between two heteroarenes via disproportionation of the copper mediator. This synthetic protocol provides a concise and "green" access to unsymmetrical biheteroarenes bearing structural motifs of substantial utility in organic synthesis.
Z. F. Mao, Z. Wang, Z. Q. Xu, F. Huang, Z. K. Yu, R. Wang, Org. Lett., 2012, 14, 3854-3857.