Cu-Catalyzed Alkylation of Grignard Reagents: A New Efficient Procedure

The presence of NMP (4–9 equiv.) clearly improves the yield and the chemoselectivity of the Cu-catalyzed alkylation of organomagnesium reagents. Thus, secondary and tertiary alkylmagnesium chlorides were used successfully for the first time in such a reaction and ester, amide, nitrile or keto groups are tolerated. The procedure is cheap, environmentally friendly and very easy to carry out (1–3% Li2CuCl4 or CuCl, THF, 20°C). It is an interesting alternative to the classical alkylation of organocuprates reagents.