Palladium-Catalyzed Vinylation of Cyclopentenes with Inverted -Isomerism of Vinylic Substrates.

A palladium-promoted Mizoroki-Heck type reaction employing a directing-group strategy to efficiently produce the coupled vinyl cyclopentenes with excellent regio- and stereoselectivity is reported. Typically, a Pd-catalyzed reaction of 2-(cyclopent-2-en-1-yl)--tosylacetamide () with ()-styryl bromides gave -2-(()-styryl)cyclopent-3-en-1-yl--tosylacetamide (), an allylic substitution product. Interestingly, we have found that the ,-stereochemistry of vinylic substrates is inverted in those products. The mechanism of this catalytic reaction is discussed.