Pd‐Catalyzed Sonogashira Cross‐Coupling Reactions of gem‐Dibromovinyl BODIPY Derivatives. Issue 22 (4th May 2021)

• Record Type: Journal Article
• Authors: Ali, Hasrat; Guérin, Brigitte; van Lier, Johan E.
• Is Part Of: European journal of organic chemistry. Volume 2022:Issue 22(2022)
• Page Start: 3123
• Page End: 3132
• Publication Date: 2021-05-04
• Subjects: BODIPY -- Sonogashira reaction -- Stille reaction -- UV/Vis -- X-ray diffraction analysis; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202100133
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: 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. Abstract : BODIPY derivatives bearing gem‐dibromovinyl moieties (α‐ or β‐positions of the pyrrole rings, directly or through phenyl spacers) undergo efficiently Sonogashira and Stille Pd‐catalyzed cross‐coupling resulting in the formation of 1, 1‐diynyl‐1‐alkene and 1, 1‐diphenyl‐1‐alkene products. A pronounced red shift of absorption maxima occurs when substituents are at the α‐position rather than the β‐position of the pyrrole ring. 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.