Alkenes from β-lithiooxyphosphonium ylides generated by trapping α-lithiated terminal epoxides with triphenylphosphine

Beilstein J Org Chem. 2012:8:1896-900. doi: 10.3762/bjoc.8.219. Epub 2012 Nov 7.

Abstract

Terminal epoxides undergo lithium 2,2,6,6-tetramethylpiperidide-induced α-lithiation and subsequent interception with Ph(3)P to provide a new and direct entry to β-lithiooxyphosphonium ylides. The intermediacy of such an ylide is demonstrated by representative alkene-forming reactions with chloromethyl pivalate, benzaldehyde and CD(3)OD, giving a Z-allylic pivalate, a conjugated E-allylic alcohol and a partially deuterated terminal alkene, respectively, in modest yields.

Keywords: alkenes; epoxides; lithiation; synthetic methods; ylide.