Tandem Thien- And Benz-annulations Of α-Alkenoyl-α-alkynyl Ketene Dithioacetals: Synthesis Of Functionalized Benzo[b] Thiophenes

Benzo[b]thiophenes represent a class of important heterocyclic compounds which are widely distributed in bioactive natural products. These heterocycles form the core of a number of medicinally important molecules. Furthermore,benzo[b]thiophenes are also widespread in catalysis and material chemistry, thus demonstrating the continuing need for the development of efficient methods to benzo[b]thiophenes.Over the past decades, ?-oxo ketene dithioacetals are emerging as versatile intermediates in organic synthesis. And the cyclization of ?-alkenoyl-?-alkynyl ketene dithioacetals is a rapid and powerful approach to prepare cyclic derivatives.The thesis developed herein an efficient and novel method leading to various benzo[b]thiophenes derivatives by using a domino annulation strategy, allowing the formation of two C-C bonds and a C-S bond in one step. The thesis includes the following four aspects.1. The development of ketene dithioacetals-participated domino reactions and the general methods for the synthesis of benzo[b]thiophenes were reviewed.2. Various polyfunctional benzo[b]thiophene derivatives were synthesis by using a novel and efficient domino reaction.3. The detailed reaction mechanism was studied by controlled experiments and HR-MS. A plausible mechanism was also proposed.4. Possible applications in the pharmaceutical industry and material science of these polyfunctional benzo[b]thiophene derivatives were forecasted.