CATALYTIC TRANSITION-METAL-MEDIATED TETRAENE CARBOCYCLIZATIONS - A NEW CARBOCYCLIZATION VIA HYDROSILYLATION

The palladium- or nickel-catalyzed carbocyclization of a tetraene substrate proceeds with incorporation of a hydrosilane to yield functionalized ring systems possessing trans-vicinal divinyl substituents on the newly formed ring, one of which is generated as an allylsilane. In one example, tributylstannane is shown to participate in the analogous cyclization reaction. Studies utilizing isotopic labeling, crossover experiments, and competition experiments provide evidence against a mechanism involving the initial hydrosilylation of one of the 1,3-diene subunits. © 1990, American Chemical Society. All rights reserved.