Various dipyrroles possess important motifs for construction of pyrrole-containing pigments. A series of 1,2-dipyrrolylethynes (4a–d) has been efficiently synthesized using an improved one-pot double Sonagashira coupling from trimethylsilylethyne and various 2-iodopyrroles. The resulting 1,2-dipyrrolylethynes were further transformed into novel indolyl-, ethenyl- and carboranyl-dipyrroles (5–7) using the Larock indole synthesis, stereoselective catalytic hydrogenation, or B10H14 . Indolyl-dipyrroles were found to selectively bind fluoride ions using one pyrrolic and the indolyl NHs, whereas the carboranyl- and ethenyl-dipyrroles are potentially valuable precursors for the synthesis of porphyrin isomers and expanded pigments.
各种二
吡咯具有构建含
吡咯色素的重要基团。我们采用改进的单锅双 Sonagashira 偶联法,从三甲基
硅基
乙炔和各种 2-
碘吡咯中高效合成了一系列 1,2-二
吡咯乙炔(4a-d)。利用 Larock
吲哚合成法、立体选择性催化加氢法或
B10H14 将得到的 1,2-二
吡咯乙炔进一步转化为新型
吲哚基、
乙烯基和
硼烷基二
吡咯(5-7)。研究发现,
吲哚基二
吡咯可以利用一个
吡咯基和
吲哚基 NH 选择性地结合
氟离子,而
硼酰基和
乙烯基二
吡咯则可能是合成
卟啉异构体和扩展色素的重要前体。