2-Chloroacetates as well as secondary and tertiary 2-chloroacetamides were successfully employed as electrophiles in the Suzuki-Miyaura cross-coupling reaction with potassium (E)- and (Z)-alkenyltrifluoroborates, affording the corresponding (E)- and (Z)-β,γ-unsaturated esters and amides in high yield.
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A catalytic asymmetric cross-coupling of α-halo carbonyl compounds with aryl metal reagents generates synthetically useful α-aryl carboxylic acid derivatives in good enantiomeric excess. The method can also be applied to enantioselective alkenylation reactions.
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The reaction between aryl- or vinylboroxines with α-diazocarbonyl compounds offers an alternative approach for α-arylation and α-vinylation of carbonyl compounds. α-Arylated or α-vinylated carbonyl compounds are formed under mild conditions.
C. Peng, W. Zhang, G. Yan, J. Wang, Org. Lett., 2009, 11, 1667-1670.
A radical alkenylation reaction of α-halo carbonyl compounds with styrylindium dichloride as well as unactivated alkenylindiums proceeded in the presence of triethylborane. The geometry of the carbon-carbon double bonds was retained. Efficient one-pot strategies were developed.
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Phosphazene P4-tBu effectively catalyzes a nucleophilic substitution reaction of gem-difluoroalkenes with ketene silyl acetals under mild conditions to provide monofluoroalkenes possessing an alkoxycarbonylmethyl group in high yields with high Z selectivities.
A. Kondoh, K. Koda, M. Terada, Org. Lett., 2019, 21, 2277-2280.
An effient cobalt-catalyzed enantioselective vinylation of α-ketoesters, isatins, and imines delivers a range of synthetically useful allylic alcohols and amines in high enantiopurity. This convenient method employs commercially available and easy to handle catalysts and reagents.
Y. Huang, R.-Z. Huang, Y. Zhao, J. Am. Chem. Soc., 2016, 138, 6571-6576.
Substituted allylic zinc reagents, prepared via direct metal insertion in substituted allylic halides, react readily with a broad range of acid chlorides and chloroformates to yield the corresponding α-substituted β,γ-unsaturated ketones and esters in high yield and perfect regioselectivity.
C. Sämann, P. Knochel, Synthesis, 2013, 45, 1870-1876.