Nickel(0) Catalyzed [2+2] Cross-addition of Bicyclo[2.2.1]heptene Derivatives with Electron-deficient Olefins

In the presence of bis(acrylonitrile)nickel(0) or bis(1,5-cyclooctadiene)nickel(0), exo-tricyclo[3.2.1.02,4]oct-6-ene cycloadds to acrylonitrile and methyl acrylate to give anti- and syn-3-cyano-exo,exo-tetracyclo[4.3.1.02,5.07,9]decane or the corresponding methoxycarbonyl derivatives. The cycloaddition with dimethyl maleate proceeds with retention of configuration. Benzonorbornadiene also enters into the 2+2 reaction, while endo-tricyclo[3.2.1.02,4]oct-6-ene, bicyclo[2.2.1]heptene, and 5-methylenebicyclo[2.2.1]heptene are unreactive. Origins of the observed selectivities in the catalyzed reaction are discussed.