Reductive Elimination of Bromine from 1,2-Dibromoalkanes Using Organometallic Reagents

Abstract

Organocuprate(I) reagents are now being widely used for highly selective substitution reactions¹ with alkyl,² alkenyl,² aryl,² and acyl³ halides and with α,α'-dihaloketones.⁴ Organocopper interaction with 1,2-dihaloalkanes is of interest because two main reaction pathways may be expected: (a) replacement of both halogens by organic groups and (b) reductive elimination of halogen to form alkenes.⁵ We report here that various types of 1,2-dibromides react with lithium dialkyl-cuprate(I) reagents under exceedingly mild conditions to give alkenes exclusively (Eq. 1).