A General Method for Acylation of Indoles at the 3-Position with Acyl Chlorides in the Presence of Dialkylaluminum Chloride.

Indoles are selectively acylated at the 3-position in high yields on treatment with a wide variety of acyl chlorides in CH2Cl2 in the presence of diethylaluminum chloride or dimethylaluminum chloride. The reaction proceeds under mild conditions and is applicable to indoles bearing various functional groups without NH protection.