Preparation of a Storable Zinc Carbenoid Species and Its Application in Cyclopropanation, Chain Extension, and [2,3]-Sigmatropic Rearrangement Reactions

The formation of a new phosphate carbenoid (n-BuO)(2)P(O)OZnCH(2)I and its application in organozinc-mediated reactions is described. This carbenoid undergoes very slow degradation in solution and can be stored for several weeks at -20 degrees C. Its reactivity was tested with many representative alkenes and was determined to be a powerful cyclopropanating reagent, giving the corresponding cyclopropanes in 72-99% yield. The use of this carbenoid in the chain extension of 1,3-diketones and [2,3]-sigmatropic rearrangement reactions is also described.