C-Acylation of 2-Methylfuran and Thiophene using N-Acylbenzotriazoles

摘要

Reactions of 2-methylfuran and thiophene with readily available N-acylbenzotriazoles (RCOBt, where R = 4-tolyl, 4-methoxyphenyl, benzyl, 4-nitrophenyl, 4-diethylaminophenyl, 2-pyridyl and 1-naphthyl) in the presence of TiCl_4 or ZnBr_2 produced 2-methyl-4-acylfurans 2a-e and 2-acylthiophenes 3a-f in average yields of 54 % and 75 %, respectively. Literature yields for the preparation of the same compounds are significantly lower.