Preparation And Properties Of Ketene Dithioacetals Containing1,5-dihydrobenzo[e][1,3]Dithiepine Structure

Ketene dithioacetals are importrant intermediates in organic synthesis. For theirstructural diversity, they could undergo versatile reactions, such as decarboxylativehalogenation, Michael addition,[3+2] cyclization and [5+1] cyclization reaction etc.Our group has been engaged in ketene dithioacetals chemistry for over twenty years, andhas carried out extensive research on the preparation and utilization of various ketenedithioacetals. Based on our previous reseach results, this thesis developed a series of phthalalketene dithioacetals and the cleavage of their Csp2-C bond was investigated. Furthermore,with the new phthalal ketene dithioacetals as the five carbon synthons, nitroethane as the onecarbon synthon, a new kind of poly-substituted cyclohexanone derivatives was developedfrom our characteristic [5+1] cyclization reaction.The synthesis of poly-substituted cyclohexanone often suffered the drawbacks such asmulti-steps reactions, utilization of expensive chemical agents or transition-metal catalysts.Herein, a series of new poly-substituted cyclohexanone derivatives was synthesized from thenew-designed phthalal ketene dithioacetals with easily available materials and without usingtransition-metal catalysts.