Chlorotrifluoromethylation of Terminal Olefins by Atom Transfer-Type Radical Reaction Catalyzed by Cobalt Complexes

A cobalt porphyrin-catalyzed chlorotrifluoromethylation reaction of olefins is described. The use of CF3SO2Cl as the CF3 radical source and a cobalt catalyst enabled the selective addition of CF3 radicals under thermal conditions. Various functional groups such as esters and Ar-X moieties, which can be reactive with low valent transition metal catalysts, were well-tolerated in this catalytic process. A highly functionalized alkaloid derivative was also tolerated as a substrate. As a demonstration of the bio-inspired catalytic system, catalytic usage of vitamin B-12, which is the commercially available form of the natural cobalt porphyrinoid, was employed, and diastereoselective chlorotrifluoromethylation of the alkaloid molecule was achieved.