Cross-Aldol Reactions of Enolizable Aldehydes

Significance

A chemo-, diastereo-, and enantio-selective cross-aldol reaction between enolizable α-branched aldehydes catalyzed by l-histidine is reported. This reaction gives access to several substituted and functionalized β-hydroxyaldehydes. In some cases the corresponding acetal was formed, which could be easily converted into the corresponding β-hydroxyaldehyde by treating it with an acidic ion exchange.