Enantioselective organocatalytic aldehyde–aldehyde cross-aldol couplings. The broad utility of α-thioacetal aldehydes

An asymmetric proline catalyzed aldol reaction with α-thioacetal aldehydes has been developed. Thioacetal bearing aldehydes readily participate as electrophilic cross-aldol partners with a broad range of aldehyde and ketone donors. High levels of reaction efficiency as well as diastereo- and enantiocontrol are observed in the production of anti-aldol adducts.