[EN] A METHOD OF CONTROLLING THE BROMINATION OF THIOPHENE DERIVATIVES<br/>[FR] PROCÉDÉ PERMETTANT DE MAÎTRISER LA BROMATION DE DÉRIVÉS DE THIOPHÈNE
申请人:KWANGJU INST SCI & TECH
公开号:WO2011155679A1
公开(公告)日:2011-12-15
Provided is a method for regioselective synthesis of a bromoalkylthiophene with improved yield. A 3-alkylthiophene is activated at -78not;C with n-BuLi for about 1.5 hour and then reacted with bromine to give a bromoalkylthiophene with good regioselectivity:
A selective and direct synthesis of 2-bromo-4-alkylthiophenes: Convenient and straightforward approaches for the synthesis of head-to-tail (HT) and tail-to-tail (TT) dihexyl-2,2′-bithiophenes
作者:Ashraf A. El-Shehawy、Nabiha I. Abdo、Ahmed A. El-Barbary、Jae-Suk Lee
DOI:10.1016/j.tetlet.2010.06.100
日期:2010.8
A straightforward method for the synthesis of 2-bromo-4-alkylthiophenes was developed, and the desired products were obtained in the highest chemical yields (>90%) reported to date. 2-Bromo-4-alkylthiophenes were synthesized by regioselective lithiating of 3-alkylthiophenes with n-BuLi and quenching with bromine at 78 degrees C. Moreover, a simple and efficient protocol for the synthesis of dihexyl-2,2'-bithiophenes was developed by employing 2-bromo-4-hexylthiophene instead of the commonly used monomer, 2-bromo-3-hexylthiophene. Kumada and Suzuki cross-coupling reactions were conducted to synthesize the desired products as head-to-tail (HT) and tail-to-tail (TT) regioisomers in high yields and excellent selectivity. (C) 2010 Elsevier Ltd. All rights reserved.