Terminal alkynes as keto-methyl equivalent toward one pot synthesis of 1,5-benzodiazepine derivatives under catalysis of Hg(OTf)2

Mercuric triflate catalyzes the reaction between 1,2-diaminobenzene and terminal alkynes to afford 2,4-disubstituted 2-methyl-2,3-dihydro-1H-benzo[b][1,4]diazepine in an excellent yield. The terminal alkynes function as a source of keto-methyl equivalent.