Highly Diastereoselective Tandem Reduction-Allylation Reactions of 1,4-Diketones with Zirconocene-Olefin Complexes

摘要

Terminal alkenes act as dual nucleophiles in a zirconocene-mediated,highly 1,4-diastereoselective,tandem reduction-allylation reaction of 1,4-diketones.A zirconocene-alkene complex(in equilibrium with an allyl-zirconocene-hydride species)can deliver both hydride and an allyl group to a diketone,with control of the relative configuration of up to three new stereogenic centers.Since Negishi and Takahashi have developed the convenient method for the generation of low-valent zirconocene species,the reaction of zirconocene-alkene complexes with a variety of unsaturated compounds has been regarded as a powerful tool for carbon-carbon bond forming processes.