Catalytic Asymmetric Mannich Reactions of Sulfonylacetates

Arylsulfonylacetates can be viewed as synthetic equivalents of a variety of alpha-carboxylate anions. Phase-transfer catalysis (PTC) enabled their mild deprotonation and catalytic asymmetric addition to highly reactive imines generated in situ from alpha-amidosulfones (see scheme; Pg=protecting group). The synthetic utility of the products was demonstrated by their straightforward transformation into a range of beta-amino acid derivatives.