Alc(L)3 Center Dot 6h(2)O-Catalyzed Friedel-Crafts Alkylation Of Indoles By The Para-Quinone Methide Moiety Of Celastrol

A classical Friedel-Crafts alkylation of different indoles catalyzed by AlCl3 center dot 6H(2)O has been developed for a well-known important natural product, celastrol, resulting in a series of derivatives for further biological evaluation. The catalyst loading was reduced to 5 mol %, the reaction proceeds at ambient temperature and reaction time is only 3 h. The product yields range from 20% to 99%. A reaction mechanism is also proposed, based on our experiment results.