Nucleophile-Catalyzed, Facile, and Highly Selective C-H Activation of Fluoroform with Pd(II)

Exceedingly facile (23 degrees C) and chemoselective H-CF3 activation with [(dppp)Pd(Ph)(OH)] in the presence of a Lewis base promoter such as n-Bu3P leads to Pd-CF3 bond formation in nearly quantitative yield. A combined experimental and computational study points to a new mechanism that involves H-bonding Pd-O(H)center dot center dot center dot H-CF3 and nucleophilic attack of the promoter on the metal, followed by a push-pull-type collapse of the resultant five-coordinate Pd(II) intermediate via a polar transition state.