11. Selectivity in Rhodium(II)-Catalyzed Rearrangements of Cycloprop-2-ene-1-carboxylates

Article abstract of DOI:10.1002/hlca.19950780113

The course of the thermocatalytic rearrangement of cycloprop-2-ene-1-carboxylates in the presence of dirhodium(II) tetrakis(perfluorobutyrate) (Rh2(pfb)4>) was investigated by varying the substituents of the cyclopropene ring.Product composition is markedly influenced by the number, nature, and position of the substituents, which determine the regio- and stereoselectivity of the cyclopropene-ring cleavage.A mechanism is proposed in which attack of the electrophilic Rh^II species is concerted with disrotatory ring opening of the incipient cyclopropyl cation and affords a metal-complexed vinylcarbene.The chemoselectivity of the latter is consistent with that of other carbenes generated in the presence of .