Tandem thia-Michael/Dieckmann condensation of allenyl esters for the regioselective synthesis of trisubstituted thiophenes
作者:Michiyasu Nakao、Munehisa Toguchi、Yuki Shimabukuro、Shigeki Sano
DOI:10.1016/j.tetlet.2020.152271
日期:2020.9
Tandem thia-Michael/Dieckmann condensation of allenyl esters with methyl mercaptoacetate in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene afforded 2,3,5-trisubstituted thiophenes regioselectively. On the other hand, 2,3,4-trisubstituted thiophenes were obtained as the sole product by tandem thia-Michael/Dieckmann condensation employing magnesium bromide and triethylamine.
在1,8-二氮杂双环[5.4.0]十一烷基-7-烯的存在下,烯丙基酯与巯基乙酸甲酯的串联硫杂-迈克尔/狄克曼缩合反应可选择性地提供2,3,5-三取代噻吩。另一方面,使用溴化镁和三乙胺,通过串联硫杂-迈克尔/狄克曼缩合反应,获得了2,3,4-三取代噻吩作为唯一产物。