A Mechanistic Dichotomy Leading to a Ruthenium-Catalyzed cis-Addition for Stereoselective Formation of (Z)-Vinyl Bromides.
Either trans- or cis-haloalkylation is possible through a three-component coupling [Eq. (1)]. The cis-bromoruthenation of an alkyne by lithium bromide and [CpRu(CH(3)CN)(3)]PF(6), catalyzed by SnBr(4), gives (Z)-vinyl bromides with high chemoselectivity. The degree of control over the sterochemistry raises intriguing mechanistic questions as well as offering practical synthetic utility.
Trost
BM
Department of Chemistry, Stanford University Stanford, CA 94305-5080 (USA).
Pinkerton
AB