First example of highly stereoselective synthesis of 1,2,3-trisubstituted cyclopropanes via chiral selenonium ylides.

As the first example of the application of chiral selenonium ylides in asymmetric cyclopropanation, a new strategy for the highly stereoselective synthesis of chiral 1,2,3-trisubstituted cyclopropanes via selenonium ylides is described. The reaction afforded three stereoisomers of chiral 1,2,3-trisubstituted cyclopropanes with good yields, excellent diastereoselectivities, very high enantioselectivities (up to >99% ee), good generality and recyclability of chiral selenides. The possible pathways and models of the asymmetric cyclopropanation via the chiral selenonium ylides were also proposed to rationalize the excellent enantioselectivities and diastereoselectivities.