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% ...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.展开更多
基金Supported by Human Resources and Social Security Department Students Abroad Science and Technology Activities Preferred Foundation (Human and Social Council Issued 2008-86)Talent Development Fund Project in Jilin Province (Jilin 2007-259)+6 种基金Jilin Province Science and Technology Development Project (20060577 )Technology Project Jilin Provincial Ministry of Education (20094352006113 2007169)The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry ( 2005-546 )Science Foundation of Changchun Teachers University (2009002)Northeast Normal University Natural Science Foundation for Young Scholar (20050406)~~
文摘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.
