Generation of 3- and 5-Lithiothiophene-2-carboxylates via Metal−Halogen Exchange and Their Addition Reactions to Chalcogenoxanthones
作者:Michael K. Gannon、Michael R. Detty
DOI:10.1021/jo062370x
日期:2007.3.1
Deprotonation and lithium−bromine exchange in 5- or 3-bromothiophene-2-carboxylic acids with t-BuLi form the corresponding dianion, which reacts highly regioselectively in the presence of 0.25 equiv of tetramethyl-1,2-ethylenediamine with 3,6-bis(dimethylamino) chalcogenoxanthones to give S- and Se-containing rhodamines. Quenching studies with D2O indicate that an extra equivalent of t-BuLi is not
在5-或3-溴噻吩-2-羧酸中与t -BuLi进行去质子化和溴化锂交换形成相应的二价阴离子,该二价阴离子在0.25当量的四甲基1,2-乙二胺与3,6-的存在下发生高度区域选择性反应双(二甲基氨基)硫属黄嘌呤,得到含S和Se的罗丹明。用D 2 O进行的淬火研究表明,在这些反应中不必额外添加等价的t -BuLi。使用t -BuLi进行去质子化比用溴噻吩-2-羧酸进行金属-卤素交换要快。