Direct Catalytic Asymmetric Mannich-Type Reaction en Route to α-Hydroxy-β-amino Acid Derivatives.
Bo SunRoman PlutaNaoya KumagaiMasakatsu ShibasakiPublished in: Organic letters (2018)
A direct catalytic Mannich-type reaction of α-oxygen-functionalized amides was achieved. The use of 7-azaindoline amide was crucial to facilitate direct enolization and subsequent stereoselective addition to imines in a cooperative catalytic system comprising a soft Lewis acid and Brønsted base. The operationally simple room-temperature protocol furnished a syn-Mannich adduct with high stereoselectivity. Divergent functional group transformation of the amide moiety of the product allowed for expeditious access to enantioenriched syn-configured α-hydroxy-β-amino carboxylic acid derivatives, highlighting the synthetic utility of the present catalysis.