Carbanion induced synthesis of dibenzo[a,c]cycloheptenes through ring transformation reactions of 2H-pyran-2-one

An efficient and convenient one-pot synthesis of 4-aryl-2-methylsulfanyl-6,7-dihydro-5H-dibenzo[a,c]cycloheptene-1-carboxylate 3a–n has been delineated and illustrated through carbanion induced ring transformation of 6-aryl-3-carbomethoxy-4-methylsulfanyl-2H-pyran-2-ones 1 with benzosuberone 2.