Ruthenium Catalyzed Rearrangement of Ene-cyclopropenes. Divergent Reaction Pathways

J Org Chem. 2019 Jan 18;84(2):924-933. doi: 10.1021/acs.joc.8b02849. Epub 2019 Jan 9.

Abstract

The reaction of ene-cyclopropenes with Cp*RuCl(cod) leads to alkenyl bicyclo[3.1.0]hexanes, bicyclo[4.1.0]heptanes, and bicyclo[5.1.0]octanes. This reaction involves a reverse regioselectivity in the cyclopropene opening than with gold chlorides. With gem-disubstituted cyclopropenes, a novel cycloisomerization based on ring-opening nucleophilic attack and rearrangement is observed. Alternatively, some gem-disubstituted cyclopropenes give dimerizations of the intermediate carbene.