Studies in sulfur heterocycles. Part 14.1 Application of heteroatom directed ortho-metallation in functionalisation of benzo[b]thiophene derivatives

Abstract

Heteroatom directed ortho-metallation of 2-tert-butyldimethylsilyl-4-methoxybenzo[b]thiophene and 2-tert-butyldimethylsilyl-4-carbamoyloxybenzo[b]thiophene has been followed by quenching with electrophiles. Anionic ortho-Fries rearrangement has been carried out on 4-carbamoyloxybenzo[b]thiophene. The rearranged product has been used as the starting material in the synthesis of a novel linearly fused thienoisochromene.