Selectivity of Br/Li Exchange and Deprotonation of 4,4鈥?Dibromo-3,3鈥?bithiophene for Synthesis of Symmetrical and Unsymmetrical Dithienoheteroaromatic Rings

详细信息    查看全文

• 作者：Hui Han ; Wenling Zhao ; Jinsheng Song ; Chunli Li ; Hua Wang
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：March 15, 2013
• 年：2013
• 卷：78
• 期：6
• 页码：2726-2730
• 全文大小：271K
• 年卷期：v.78,no.6(March 15, 2013)
• ISSN：1520-6904

文摘

The novel selective synthesis of symmetrical and unsymmetrical dithienoheteroaromatic rings (DTHAs) has been developed via intramolecular cyclization of 4,4鈥?dibromo-3,3鈥?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鈥?b>c). The possible mechanism of formation of DTHAs was proposed. In addition, two unsymmetrical DTHAs were confirmed by X-ray single-crystal analyses.