Phosphine-catalyzed domino reaction: highly stereoselective synthesis of trans-2,3-dihydrobenzofurans from salicyl N-thiophosphinyl imines and allylic carbonates.

A novel phosphine-catalyzed domino reaction of salicyl N-thiophosphinyl imines and allylic carbonates was developed. The allylic carbonate, in this reaction, serves as a new kind of 1,1-dipolar synthon. This method offered a powerful approach to the construction of a highly substituted trans-2,3-dihydrobenzofuran skeleton with high diastereoselectivity.