Catalytic Asymmetric Mannich Reactions of Sulfonylacetates

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