Key points are not available for this paper at this time.
Teaming up: The title reaction has been developed to deliver the product α-alkylidene-γ-butyrolactones as single diastereomers with up to 98 % ee (see scheme; Ts=4-toluenesulfonyl). The enantioselective process is catalyzed by 1, which contains both Lewis base and Brønsted acid moieties.
Takizawa et al. (Wed,) studied this question.