Enantioselective Direct Aldol-Tishchenko Reaction: Access to Chiral Stereopentads
摘要:
The aldol-Tishchenko reaction of aromatic aldehydes in the presence of titanium(IV) tertbutoxide and amino alcohols is described. When used with cinchona alkaloids, stereopentads were isolated for the first time with a high degree of diastereo- and enantioselectivity.
Simple aminoacid-derived esters have been identified as promising chiral sources for the ytterbium-catalyzed aldol-Tishchenkoreaction of aromatic aldehydes with aliphatic ketones. The 1,3-anti-diols with three stereogenic centers were isolated in excellent yields, complete anti-diastereocontrol and enantioselectivities of up to 50% ee.
The first example of a catalytic asymmetric aldol-Tishchenko reaction of aldehydes and aliphatic ketones
作者:Jacek Mlynarski、Marcin Mitura
DOI:10.1016/j.tetlet.2004.08.134
日期:2004.10
condensation––Evans–Tishchenko reduction of aldehydes and ketones. Chiral ytterbium complexes were found to catalyze the condensation of aromaticaldehydes with 3-pentanone (and other ketones) giving rise to the anti-1,3-diol monoesters in good yield, and with high diastereocontrol and moderate levels of enantioselectivity. Three adjacent stereogenic centers are created in one reaction sequence in acyclic systems
Enantioselective Direct Aldol-Tishchenko Reaction: Access to Chiral Stereopentads
作者:Kerstin Rohr、Robert Herre、Rainer Mahrwald
DOI:10.1021/ol0517675
日期:2005.9.1
The aldol-Tishchenko reaction of aromatic aldehydes in the presence of titanium(IV) tertbutoxide and amino alcohols is described. When used with cinchona alkaloids, stereopentads were isolated for the first time with a high degree of diastereo- and enantioselectivity.