Catalytic Asymmetric Mukaiyama–Mannich Reaction of Cyclic <i>C</i>‑Acylimines with Difluoroenoxysilanes: Access to Difluoroalkylated Indolin-3-ones

A catalytic enantioselective Mukaiyama–Mannich reaction of cyclic <i>C</i>-acylimines with difluoroenoxysilanes is reported. (<i>S</i>)-TRIP enables the enantioselective synthesis of a series of novel difluoroalkylated indolin-3-ones bearing a quaternary stereocenter in up to 97% yield and 98% ee. The synthetic utility of this protocol is highlighted by efficient conversion of the products to the corresponding indolin-3-one derivatives without any erosion of the enantiopurity