Ruthenium(II)- and rhenium(III)-catalysed addition of tetrahalogenomethanes to alkenes and 1,ω-dienes. Stereoselective formation of cis-1,2-disubstituted cyclopentanes from 1,6-dienes

Abstract

Acetonitrile(trichloro)bis(triphenylphosphine)rhenium(III) is found to act as an initiator for the addition of carbon tetrachloride and bromotrichloromethane to terminal alkenes and dienes. Moderate to good yields of mono- and bis-adducts are obtained. 1,6-Dienes undergo a stereoselective addition-cyclization process with both the Re^III catalyst and with dichlorotris(triphenylphosphine)ruthenium (II) to give mixtures of cis- and trans-3-halogenomethyl-4(2,2,2-trichloroethyl)cyclopentanes in which the cis-isomers predominate. The stereoselectivity is discussed and evidence presented for the Re^III complex acting as a simple initiator.