title: Selectivity of Br/Li exchange and deprotonation of 4,4'-dibromo-3,3'-bithiophene for synthesis of symmetrical and unsymmetrical dithienoheteroaromatic rings.
abstract: The novel selective synthesis of symmetrical and unsymmetrical dithienoheteroaromatic rings (DTHAs) has been developed via intramolecular cyclization of 4,4'-dibromo-3,3'-bithiophene (3). Four reaction conditions including n-BuLi/Et2O, n-BuLi/THF, s-BuLi/Et2O, and t-BuLi/Et2O were employed to react with 3 for selective formation of two types of dicarbanions, which generate the symmetrical and unsymmetrical DTHAs after quenching with three electrophilic reagents (4a-c). The possible mechanism of formation of DTHAs was proposed. In addition, two unsymmetrical DTHAs were confirmed by X-ray single-crystal analyses.
authors: Key Lab for Special Functional Materials of Ministry of Education, Henan University, Kaifeng 475004, China.
authors: Hui
authors: H
authors: Han
authors: Wenling
authors: W
authors: Zhao
authors: Jinsheng
authors: J
authors: Song
authors: Chunli
authors: C
authors: Li
authors: Hua
authors: H
authors: Wang