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Pd‐Catalyzed Sonogashira Cross‐Coupling Reactions of gem ‐Dibromovinyl BODIPY Derivatives
Author(s) -
Ali Hasrat,
Guérin Brigitte,
Lier Johan E.
Publication year - 2021
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202100133
Subject(s) - sonogashira coupling , chemistry , alkene , pyrrole , photochemistry , bodipy , protonation , medicinal chemistry , stille reaction , coupling reaction , annulene , fluorescence , catalysis , stereochemistry , palladium , organic chemistry , ion , physics , quantum mechanics
4,4‐Difluoro‐4‐bora‐3a,4a‐diaza‐ s ‐indacene (BODIPY) derivatives bearing gem ‐dibromovinyl moieties at either the β‐ or α‐positions of the pyrrole rings, directly or through phenyl spacers, undergo efficiently Sonogashira and Stille Pd‐catalyzed cross‐coupling. The structures of the resulting 1,1‐diynyl‐1‐alkene and 1,1‐diphenyl‐1‐alkene products were assigned using MS, NMR and in some cases X‐ray diffraction analysis. 1,1‐Diynyl‐1‐alkene BODIPYs exhibit red shifted absorption maxima, particularly when substituents were introduced at the α‐position rather than the β‐position of the pyrrole ring. Aromatic compounds showed larger red shifts as compared to the aliphatic substituted analogs. The highest red shifts were observed with compounds featuring electron donating substituents. Spectroscopic properties of α‐substituted 1,1‐diynyl‐ p ‐N,N‐dimethylaminophenyl‐1‐alkenes are sensitive to protonation resulting in remarkable pH‐responsive changes in the absorption and fluorescence emission spectra.