Bimetallic catalytic systems containing Ti, Zr, Ni, and Pd. Their applications to selective organic syntheses
Controlled carbometallation of unnactivated acetylenes represents a new methodology in organic synthesis. We have found that the Zr-catalyzed carboalumination of terminal alkynes provides a highly selective and versatile entry into trisubstituted olefins, especially those of terpenoid origin. Its scope, synthetic applications, and mechanism are discussed with emphasis on the cross-coupling reactions of alkenylalanes with organic halides catalyzed by palladium and nickel complexes.