The catalytic asymmetric aldol reaction of silyl ketene acetals with aldehydes in the presence of a chiral borane complex. Nitroethane as a highly effective solvent for catalytic conditions
作者:Syun-ichi Kiyooka、Yuichi Kaneko、Ken-ichi Kume
DOI:10.1016/s0040-4039(00)61236-4
日期:1992.8
Catalyticasymmetric aldol reactions of silyl ketene acetals with aldehydes in the presence of 20 mol % of the chiral borane reagent, prepared in situ from the p-nitrobenzenesulfonamide of (S)-valine and BH3·THF complex, gave β-hydroxy carboxylic acid esters in good chemical yields along with excellent enantioselectivity under conditions that employ nitroethane as an effective solvent.
The catalytic asymmetric aldol reaction of aldehydes with unsubstituted and monosubstituted silyl ketene acetals: formation of anti-β-hydroxy-α-methyl esters
作者:Emma R. Parmee、Yaping Hong、Orin Tempkin、Satoru Masamune
DOI:10.1016/s0040-4039(00)91717-9
日期:1992.3
The title reaction with unsubstituted and monosubstituted silyl ketene acetals proceeds with high enantioselectivity, and in the latter case good diastereoselectivity favoring the anti-β-hydroxy-α-methyl esters in all reported cases.
Kinetic Resolution of Quaternary and Tertiary β-Hydroxy Esters
作者:Derek J. Schipper、Sophie Rousseaux、Keith Fagnou
DOI:10.1002/anie.200902373
日期:2009.10.19
Selectivity factors: The resolution of tertiary and secondary alcohols, which arise from ketone and aldehyde aldol additions, proceeds in the presence of (1S,2R)‐N‐methylephedrine (see example). The method is technically simple, easily scalable, and provides tertiary and secondary alcohols in high enantiomeric ratios.