Study On The Sonogashira Reaction Of α-iodo Ketene Dithioacetals

Sonogashira reaction was first reported in1975. It’s an extremely powerful syntheticmethod for the synthesis of conjugated enynes and other important organic intermediates,which often encountered within natural products, molecular materials, pharmaceuticalmolecules or synthetic agrochemicals. The typical Sonogashira reaction usually containspalladium(0) as catalyst and copper(I) salts as co-catalyst. About this reaction, during the pastfew years, people have made a lot of research and exploration, and obtained some importantachievements. Much advance has been made, but the reaction will still continue to be afast-moving topic in the field of organic chemistry.In the past few years, systematic studies on the ketene dithioacetals and its furtherapplications have been made in our group. Based on the research achievements our grouphave made in the past decades, much new work has been developed in this paper, Especiallywith α-iodo-α-carbonyl ketene cyclic dithioacetals being as the research objects. In order tobetter realize the coupling procedure of α-iodo-α-carbonyl ketene cyclic dithioacetals andterminal acetylenes, precise measurement for more convenient reaction conditions has beenmade in my article. The paper mainly includes the following aspects：(1) At room temperature, a new method has been used for the preparationof α-iodo-α-carboxylate ketene cyclic dithioacetals.(2) Under the catalysis of Pd(PPh3)4along with CuCl as co-catalyst, Sonogashira reactionof α-iodo-α-carbonyl ketene cyclic dithioacetals and terminal acetylenes occurred smoothlyin THF at60℃.(3) A series of new conjugated enynes which could have potential values have been madein this paper.