Stereoselective Preparation of CF3-Containing Cyclopropanes.

A regio- and diastereoselective carbometalation of easily accessible CF3-substituted cyclopropenes is developed with a diastereoselectivity of the addition opposite to the CF3 group. This simple strategy allows the preparation of polysubstituted (up to penta-) cyclopropyl rings possessing two adjacent quaternary carbon stereocenters with excellent diastereoselectivities.