Regioselective 1,4-Addition to α,β-Unsaturated Ketones with Grignard Reagents Mediated by (N,N,N',N'-Tetramethylethylenediamine)zinc(II) Chloride

Article abstract of DOI:10.1021/jo00371a015

The reaction of α,β-unsaturated ketones with a THF solution RMgX (3 mol equiv) and ZnCl2*TMEDA (1 mol equiv) followed by NH4Cl gave 1,4-addition products.The products were contaminated by 1,2-addition products when R = Ph and Me but were essentially free of those compounds when R = n-Bu or i-Pr.The yields were highest when X = Cl.Thus the reaction of 2-cyclohexen-1-one with a solution of n-BuMgCl and ZnCl2*TMEDA gave 3-n-butylcyclohexanone (1) in 96percent yield.