TEMPERATURE DEPENDENCY OF DIASTEREOSELECTIVITY IN THE ALDOL REACTION OF TRIBUTYLSTANNYL ENOLATES WITH BENZALDEHYDE

At −50°C the O-stannyl enolate reacts with benzaldehyde more quickly than the corresponding C-stannyl derivative to give predominantly threo adduct, which slowly isomerizes into the erythro isomer on warming the reaction products. At r.t. the stannyl enolate reacts rapidly to yield the erythro product.