Nickel(0)-Catalyzed Reactions of Bicyclobutanes. Geminal Two-Bond Cleavage Reaction and the Stereospecific Olefin Trapping of the Carbenoid Intermediate.

Article abstract of DOI:10.1021/jo00327a004

Zerovalent nickel complexes such as bis(acrylonitrile)nickel(0) or bis(1,5-cyclooctadiene)nickel(0) catalyze the reaction of bicyclo<1.1.0>butanes and electron-deficient olefins such as methyl acrylate and acrylonitrile to give the corresponding allylcyclopropane derivatives in excellent yields.The reaction of 3-deuterio-1,2,2-trimethylbicyclo<1.1.0>butane indicates that the two-bond cleavage occurs at the central ? bond and one of the four peripheral bonds of bicyclo<1.1.0>butanes to generate an allylcarbene-nickel complex as the reactive intermediate.The reactionof bicyclo<1.1.0>butane with (Z)-β-deuterioacrylate or a pair of E and Z 1,2-disubstituted olefins proceeded with a high degree of stereospecificity.The mechanism of cycloaddition is discussed.