Rh(i)-catalyzed dimerization of ene-vinylidenecyclopropanes for the construction of spiro[4,5]decanes and mechanistic studies

Abstract

Rh(I) complex catalyzed dimerization of ene-vinylidenecyclopropanes took place smoothly to construct a series of products containing spiro[4,5]decane skeletons featuring a simple operation procedure, mild reaction conditions, and good functional group tolerance. In this paper, the combination of experimental and computational studies reveals a counterion-assisted Rh(I)–Rh(III)–Rh(V)–Rh(III)–Rh(I) catalytic cycle involving tandem oxidative cyclometallation/reductive elimination/selective oxidative addition/selective reductive elimination/reductive elimination steps; in addition, a pentavalent spiro-rhodium intermediate is identified as the key intermediate in this dimerization reaction upon DFT calculation.