Highly diastereoselective addition of cyanide to β-hydroxyketones
摘要:
The addition of cyanide with KCN/ZnI2/TMSCN to beta-hydroxyketones (R1-CHOH-CO-R2, R1 = i-Pr, R2 = Me, Et, i-Bu, i-Pr, t-Bu, R1 = Et, R2 = t-Bu and R1 = Bn, Ph, R2 = i-Bu) produced syn beta-hydroxycyanohydrins in 95% d.e.
The Chemistry of Trichlorosilyl Enolates. Aldol Addition Reactions of Methyl Ketones
作者:Scott E. Denmark、Robert A. Stavenger
DOI:10.1021/ja001023g
日期:2000.9.1
observed in this uncatalyzed aldol process. The aldol additions are dramatically accelerated by the addition of catalytic quantities of chiral phosphoramides, particularly one derived from N,N‘-dimethylstilbene-1,2-diamine. In this catalyzed mode, good to high enantioselectivities are obtained with a variety of achiral trichlorosilyl enolates and aldehydes. When either partner bears a stereogenic center
Stereoselective addition of organometallic reagents to β-hydroxyketones
作者:José Luis Garcia Ruano、Amelia Tito、Rafael Culebras
DOI:10.1016/0040-4020(95)01048-3
日期:1996.2
Reactions of several β-hydroxyketones with different methylation reagents are reported. The de's are moderated or good (40–75%) and slightly change with the relative steric size of the R groups at the starting hydroxyketone. The syn-diols are predominant in reactions with Me3Al/ZnBr2 and MeLi/Me3Al, whereas the anti-diols are the major ones with MeLi/ZnBr2. The method has been used to synthesize optically