Synthesis of 2-(1-methyl-4-piperylid-3-ene)-9,10-dihydro-4H-benzo[4,5]- cyclohepta[1,2-b]thiophen-10-one,a new potential antiasthmatic analogue of zaditene

The title compound has been prepared in four steps from readily available starting material. The key reaction is the metallation of 10-methoxy-4H-benzo[4,5]cyclohepta[1,2-b]thiophene, which occurs exclusively at the desired 2 position.