Efficient synthesis and reactions of 1,2-dipyrrolylethynes

Abstract

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.

One‐Pot Synthesis of Butadiyne‐Bridged Bipyrrole Derivatives and Bisporphyrin

“…Whereas the presence of unreacted starting material could be attributed to the formation of diacetylene (or butadiyne)‐bridged bipyrroles, the formation of the latter may be ascribed to the presence of a trace amount of oxygen in the reaction medium, which might have promoted oxidative coupling. While we were working on this theme, Vicente and co‐workers reported the synthesis of 1,2‐dipyrrolylethynes following this strategy However, comparatively lower yields reported by them did not rule out the formation of the butadiyne derivatives in their case as well. Following this protocol, functionalized acetylene‐bridged bipyrrole derivatives 6a – e were synthesized in varying yields depending on the nature of the substituents at the α position of the 3,4‐diethylpyrrole moiety (Table , entries 1–5).…”

Azaheterocyclic Derivatives of ortho-Carborane: Synthetic Strategies and Application Opportunities

“…The carboranyldipyrrole 93 demonstrates a high fluorescence yield of 98%. 44 According to data from electrochemical studies, these carborane-containing systems are able to produce rather effective electroactive and conducting polypyrrole films. 45…”

Porphycenes and Related Isomers: Synthetic Aspects

“…The general outline for synthesis of the precursors was reported by Vogel and co-workers 156 in 1990 and refined by Kim and coworkers 157 and Vicente and co-workers. 158 More recently, in 2015, this methodology was adapted by Kim, Panda, and coworkers 159 to prepare the β-octamethoxy-substituted 22π and 26π extended porphycenes 185f and 187f. The synthetic pathway starts with a Sonogashira coupling of iodopyrroles 63f and (trimethylsilyl)acetylene.…”

“…The second family of extended porphycenes requires the preparation of bis­(pyrroles) linked by one ( 184 ) or two alkyne units ( 186 ). The general outline for synthesis of the precursors was reported by Vogel and co-workers in 1990 and refined by Kim and co-workers and Vicente and co-workers . More recently, in 2015, this methodology was adapted by Kim, Panda, and co-workers to prepare the β-octamethoxy-substituted 22π and 26π extended porphycenes 185f and 187f .…”