[reaction--see text] Indoles are selectively acylated at the 3-position in high yields on treatment with a wide variety of acyl chlorides in CH(2)Cl(2) 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.
A new facile entry to the synthesis of 1,3-bis(indol-3-yl)butane-1-ones is presented. The procedure effectively utilizes a InBr 3 /TMSCl mixture (10 mol%) as a promoter for the chemoselective Michael addition of variously functionalised indoles to α,β-unsaturated indolyl ketones. The excellent yields and the mildness of the experimental conditions guarantee a widespread applicability of the protocol