Stereoselective Preparation of CF 3 -Containing Cyclopropanes

A regio-and diastereoselective carbometalation of easily accessible CF 3-substituted cyclopropenes is developed with a diastereoselectivity of the addition opposite to the CF 3 group. This simple strategy allows the preparation of polysubstituted (up to penta-) cyclopropyl rings possessing two adjacent quaternary carbon stereocenters with excellent diastereoselectivities