A Rh(II)-catalyzed highly stereoselective [3 + 2] annulation of vinyl diazoacetates with indole-2-carbaldehyde for the synthesis of indolyl dihydrofurans.

A highly stereoselective Rh2(Oct)4-catalyzed [3 + 2] cycloaddition of vinyl diazoacetates with indolyl aldehyde has been developed. This protocol provides an efficient access to both cis and trans indolyl dihydrofurans with high yields and diastereoselectivities under mild conditions without or with Lewis acid as additive, respectively. Moreover, these generated functionalized dihydrofurans exhibit potent antiproliferation activity in three different cancer cell lines.