Addition of benzylzinc halides to alkenyl(phenyl)iodonium triflates: stereoselective synthesis of trisubstituted alkenes

Benzylic organozinc reagents generated by insertion of zinc metal into benzyl-bromine bonds react with alkenyl(phenyl)iodonium triflates to provide single stereoisomers of trisubstituted olefins. The extremely high reactivity of the phenyliodonio moiety allows these reactions to be performed in the absence of copper salts or palladium catalysts. The reaction is performed from -40 degrees C to room temperature in THF. Excellent yields of the desired cross-coupled products have been obtained despite the occurrence of a competing electron-transfer-induced fragmentation.