Asymmetry in the boronic acid Mannich reaction: Diastereocontrolled addition to chiral iminium species derived from aldehydes and (S)-5-phenylmorpholin-2-one
(S)-5-Phenylmorpholin-2-one dagger and a range of aliphatic aldehydes form chiral iminium. intermediates which undergo diastereoselective Mannich reactions with 2-furylboronic acid, Single crystal X-ray analysis of methylated derivative 4 derived from. major adduct 2g confirms the stereochemical course of the reaction.