Condensation of СН-acids with cis-1,4-dichlorobut-2-ene
Synthesis of tri- and five-membered carboxylates are discussed. Microwave irradiation has been shown to stimulate the condensation of СН-acids with allyl chlorides. The selectivity of formation of target products was depending on the CH-acid structure. St
Enantioselective biocatalytic reduction of 2,2-disubstituted ethylacetoacetates: An indirect desymmetrization approach for the synthesis of enantiopure (S)-4-hydroxy-3,3-disubstituted pentane-2-ones
Ethyl 2,2-disubstituted-3-oxobutanoates were biocatalytically reduced to the corresponding (S)-ethyl 3-hydroxy-2,2-disubstitutedbutanoate with the growing cells of Klebsiella pneumoniae (NBRC 3319) with excellent enantioselection. The biocatalytically derived enantiopure hydroxyl esters were then synthetically manipulated to give (S)-4-hydroxy-3,3-disubstituted pentane-2-ones. The whole process can be regarded as an indirect enantioselective enzymatic desymmetrization method for the synthesis of (S)-4-hydroxy-3,3-disubstituted pentane-2-ones.
Halder, Joydev,Das, Debabrata,Nanda, Samik
p. 1197 - 1208
(2015/10/28)
An unexpected directing effect in the asymmetric transfer hydrogenation of α,α-disubstituted ketones
α,α-Disubstituted ketones containing an aromatic ring or alkene are reduced in high enantiomeric excess using an asymmetric transfer hydrogenation catalyst. The sense of reduction indicates that the unsaturated region of the ketone adopts a position adjacent to the Ru-bound η6-arene ring in the reduction transition state.
Soni, Rina,Collinson, John-Michael,Clarkson, Guy C.,Wills, Martin
p. 4304 - 4307
(2011/10/11)
Controllable cyclization reactions of 2-(2′,3′-allenyl) acetylacetates catalyzed by gold and palladium affording substituted cyclopentene and 4,5-dihydrofuran derivatives with distinct selectivity
Efficient room-temperature syntheses of cyclopentenes and 4,5-dihydrofurans with different substitution patterns were performed starting from the same materials (i.e., 2-(2′,3′-allenyl)acetylacetates). Depending on the choice of metal catalyst, the Au-cat