Asymmetric Cyclopropanation of Olefins with an in situ Generated Phenyliodonium Ylide

A procedure for the in situ generation of the phenyliodonium ylide (2) derived from Meldrum's acid (1) and its Rh(II)-catalyzed decomposition to afford an intermediate metallocarbene is described. In the presence of olefins, cyclopropanes are formed with yields and enantioselectivity comparable to that resulting from cyclopropanation with the isolated ylide 2.