Regiocontroled Pd-catalysed C5-arylation of 3-substituted thiophene derivatives using a bromo-substituent as blocking group
作者:Mariem Brahim、Hamed Ben Ammar、Jean-François Soulé、Henri Doucet
DOI:10.3762/bjoc.12.210
日期:——
C5-position via Pd-catalysed direct arylation. With 1 mol % of a phosphine-free Pd catalyst, KOAc as the base and DMA as the solvent and various electron-deficient aryl bromides as aryl sources, C5-(hetero)arylated thiophenes were synthesized in moderate to high yields, without cleavage of the thienyl C-Br bond. Moreover, sequential direct thienyl C5-arylation followed by Pd-catalysed direct arylation or Suzuki
在3-取代的噻吩的C 2-位上使用溴取代基作为保护基团允许通过Pd催化的直接芳基化在C 5-位上选择性引入芳基取代基。用1 mol%的无膦Pd催化剂,以KOAc为碱,以DMA为溶剂和各种电子缺陷的芳基溴化物作为芳基源,可以中等至高收率合成C5-(杂)芳基噻吩,而不会裂解噻吩基C-Br键。此外,顺序的直接噻吩基C5-芳基化,然后在C2-位进行Pd催化的直接芳基化或Suzuki偶联,仅需两个步骤即可制备带有两个不同的(杂)芳基单元的2,5-二(杂)芳基噻吩。这种方法提供了“绿色”