N-trimethylsilyloxyenamines as new aldehyde enolate synthons: general, efficient and diastereoselective aldol reaction with ketals and acetals.

(E)-N-trimethylsilyloxyenamines, easily accessible from aldonitrones, proved to be excellent nucleophiles in TMSOTf-induced diastereoselective aldol reaction, both with ketals and acetals, proceeding via an extended transition state and leading to a new aldol C-C-bond in the aldonitrone products, that can be readily hydrolysed to the corresponding aldehydes.