Abstract The conjugate addition of cis-or trans-1-alkenyl-cuprolithium complexes (R [BOND] CH [DOUBLE BOND] CH [BOND]) 2 CuLi· X n 1 to α, β-unsaturated carbonyl compounds was found to occur with high retention of double bond geometry, affording isomerically pure cis-or trans-γ, δ-ethylenic carbonyl compounds. The same 1-alkenylcuprates also react stereospecifically with alkyl halides to give isomerically pure cis-or trans-olefins.
