Mg-promoted regioselective cross-coupling of stilbene derivatives with carbonyl compounds

Treatment of stilbene derivatives with aliphatic carbonyl compounds in the presence of trimethylsilyl chloride (TMSCl) and Mg metal in N,N-dimethylformamide (DMF) at room temperature brought about regioselective cross-coupling to give the corresponding phenethyl alcohols in moderate to good yields. These reactions may be initiated through one-electron transfer from Mg metal to the carbon-carbon double bond of stilbene derivatives to give the cor responding anion radical species, which were subjected to electrophilic attack of aliphatic carbonyl compounds followed by fast second electron transfer generating the corresponding alpha-benzyl anions.