title: CpRuCl(PPh3)2-catalyzed cyclopropanation of bicyclic alkenes with tertiary propargylic acetates.
abstract: The electron-rich cyclopentadienylruthenium complex CpRuCl(PPh3)2 turns out to be an efficient catalyst for the regio- and stereoselective cyclopropanation of bicyclic alkenes with tertiary propargylic carboxylates. The reaction provides 1,2,3-trisubstituted cyclopropanes in high yields as a single stereoisomer instead of the expected cyclobutenes via [2 + 2] cycloaddition. Functional groups such as ethers, esters, alcohols, phenols, ketones, esters, carboxylic anhydrides, nitriles, halides, sulfones, imides, carbamates, and azines are tolerated with the catalyzed reaction. An efficient cyclopropanation of cyclobutenes was also demonstrated, providing the strained bicyclo[2.1.0(1,3)]pentane framework.
authors.affiliation: Laboratoire de Synthèse Asymétrique, UMR CNRS 6180, Université Paul Cézanne, EGIM Sud, Av. Escadrille Normandie Niemen, F-13397 Marseille Cedex 20, France. alphonse.tenaglia@univ.u-3mrs.fr
authors.forename: Alphonse
authors.initials: A
authors.lastname: Tenaglia
authors.forename: Sylvain
authors.initials: S
authors.lastname: Marc