α,α-二乙酰基二苄硫缩烯酮的碱催化脱乙酰基反应及缩合反应机理研究  

Studies on the Mechanism of Deacylation and Condensation Reactions of α,α-Diacetyl Ketene Dibenzylthioacetal

作　　者：艾林[1] 肖幼萍[2] 刘群[1] 张前[1] 王芒[1] 

机构地区：[1]东北师范大学化学学院 [2]长春教育学院化学系,长春130061

出　　处：《高等学校化学学报》2004年第5期877-879,共3页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金 (批准号 :2 0 2 72 0 0 8);教育部科学技术研究重点项目基金(批准号 :0 3 0 5 9)资助

摘　　要：The behavior of α,α-diacetyl ketene dibenzylthioacetal 1a under basic conditions was studied. Catalyzed by steric hindered base as t-BuONa(in t-BuOH), α-acetyl ketene dibenzylthioacetal 2a could be obtained in 98% yield within 3 min via deacylation of 1a. Assisted by t-BuONa(in t-BuOH), α-cinnamoyl ketene dibenzylthioacetals were produced in high yields by reacting both 1a and 2a with arylaldehydes; whereas, under the same conditions, the corresponding α,α-dicinnamoyl ketene dibenzylthioacetals 4 were formed when furan-2-carbaldehyde and thiophene-2-carbaldehyde were used as the electrophiles. These evidences support the proposed mechanism that, catalyzed by t-BuONa (in t-BuOH), the reaction of 1a with arylaldehydes may normally proceed via a sequential deacylation-condensation process and the formation of double condensation products 4 may be due to the higher activity of furan-2-carbaldehyde and thiophene-2-carbaldehyde under the selected reaction conditions.The behavior of α,α-diacetyl ketene dibenzylthioacetal 1a under basic conditions was studied. Catalyzed by steric hindered base as t-BuONa(in t-BuOH), α-acetyl ketene dibenzylthioacetal 2a could be obtained in 98% yield within 3 min via deacylation of 1a. Assisted by t-BuONa(in t-BuOH), α-cinnamoyl ketene dibenzylthioacetals were produced in high yields by reacting both 1a and 2a with arylaldehydes; whereas, under the same conditions, the corresponding α,α-dicinnamoyl ketene dibenzylthioacetals 4 were formed when furan-2-carbaldehyde and thiophene-2-carbaldehyde were used as the electrophiles. These evidences support the proposed mechanism that, catalyzed by t-BuONa (in t-BuOH), the reaction of 1a with arylaldehydes may normally proceed via a sequential deacylation-condensation process and the formation of double condensation products 4 may be due to the higher activity of furan-2-carbaldehyde and thiophene-2-carbaldehyde under the selected reaction conditions.

关 键 词：α α-二乙酰基二苄硫缩烯酮 碱催化 脱乙酰基反应 缩合反应 反应机理 

分 类 号：O626.12[理学—有机化学]