Abstract In connection with another study underway in this lab we have been investigating the use of vinylogous thioester 1 as a synthon for sesquiterpene synthesis. We have found that 1 is useful for ring annelations and introduction of multiple substituents when pursuing carbocyclic synthesis. In recent studies with thioesters we have found that the lithium enolate of 1 (LDA/THF) will undergo 1, 4-addition to Michael acceptors such as ethyl vinyl ketone ( ...