A Way to Highly Enantiomerically Enriched aza‐Morita–Baylis–Hillman–Type Products

Going Mannich: Difficult to synthesize β-amino carbonyl compounds bearing α-alkylidene groups have been prepared enantioselectively (up to 99 % ee) by reaction of β-substituted α,β-unsaturated aldehydes and α-imino esters in the presence of (S)-proline and imidazole under mild conditions (see scheme, PMP=p-methoxyphenyl). Studies suggest that the reaction mechanism involves a Mannich-type reaction/isomerization sequence.