A Novel Approach towards 2,3,5-Trisubstituted Thiophenesvia tandemMichael addition/intramolecularKnoevenagel condensation
作者:Daniel Obrecht、Fernand Gerber、Daniel Sprengeir、Thierry Masquelin
DOI:10.1002/hlca.19970800217
日期:1997.3.24
easily available, highly functionalized acetylenic ketories 4a–i (Scheme 1), novel 2,3,5-trisubstituted thiophenes 1a–i (Scheme 2) were synthesized in good yields using a tandem Michael-addition/intramolecular Knoevenagel-condensation strategy, featuring Cs2CO3/MgSO4 (1:2) as an efficient base to effect the cyclization. Subsequent simple one-step transformations yielded 2,3-disubstituted thiophene-5-carbaidehydes
从容易得到的起始,高功能化的炔属ketories 4A-I (方案1),新颖的2,3,5-三取代的噻吩1A-I (方案2)以良好的收率使用串联合成迈克尔-addition /分子内的Knoevenagel -condensation该策略以Cs 2 CO 3 / MgSO 4(1:2)作为有效环化的有效碱。随后的简单一步转化即可生成2,3-二取代的噻吩-5-碳酸酐7a–c,羧酸衍生物8、9和11,以及醇10(方案3)。这些分子构成了有趣的新型含噻吩结构单元,可用于通过组合化学和平行化学技术制备低分子量化合物文库。