Organocatalytic C─O Bond Cleavage and Asymmetric Transformations via [1,3]-Sigmatropic Rearrangement.

Here, an organocatalytic asymmetric [1,3]-sigmatropic rearrangement process for aryl ether insertion through C─O bond cleavage and downstream transformation is reported, enabling the practical and atom-economic synthesis of diverse valuable chiral benzofuran derivatives bearing a quaternary carbon stereocenter. The reaction shows a wide substrate scope, yielding moderate to good products with excellent enantioselectivity and diastereoselectivity (up to >99% ee and >99:1 d.r.). Initial biological activity tests suggest that the resulting enantioenriched benzofuran products hold potential as anticancer agents.