Differently substituted 4-(1,3-dithiolan-2-ylidene)but-1-ynes were conveniently converted into the corresponding thiophenes and dihydrothiophenes in good to high yields under mild conditions. 1,3-Dithiolan-2-ylidene acted as a masked thiolate anion and underwent tandem fragmentation and 5-exo-dig annulation with an alkyne moiety to form the five-membered sulfur heterocycles.
在温和的条件下,不同取代的 4-(1,3-dithiolan-2-ylidene)but-1-ynes 可以方便地转化为相应的
噻吩和二氢
噻吩,产率很高。1,3-Dithiolan-2-ylidene 作为掩蔽的
硫醇阴离子并与
炔烃部分进行串联断裂和 5-exo-dig 环化以形成五元
硫杂环。