β-AlkenylBODIPY Dyes: Regioselective Synthesis via Oxidative C–H Olefination, Photophysical Properties, and Bioimaging Studies

Abstract

A series of 2-alkenyl- and 2,6-dialkenylboron dipyrromethene (BODIPY) derivatives were synthesized through Pd­(II)-catalyzed regioselective and stereoselective oxidative C–H olefination in one step. The 2-alkenyl BODIPY derivative further reacted with various amines regioselectively at the 5-position through direct oxidative nucleophilic substitution. The photophysical properties of the 2-alkenyl- and 2,6-dialkenyl-substituted BODIPYs were investigated, which showed great potential in fluorescent bioimaging.

Preparation of Viscosity-Sensitive Isoxazoline/Isoxazolyl-Based Molecular Rotors and Directly Linked BODIPY–Fulleroisoxazoline from the Stable meso-(Nitrile Oxide)-Substituted BODIPY

“…Indeed, the fluorescence quantum yields measured in DCM for 14a , 14b , and 15 were found to be between 0.09 and 0.27, whereas those for the other BODIPYs vary between 0.014 and 0.05 in the same solvent (Table ). Such behavior is characteristic of BODIPY-based molecular rotors (including those with five-membered nonconjugated heterocycles located at the meso -position reported earlier), in which twisted intramolecular charge transfer (TICT) plays a dominant role in suppressing of fluorescence. BODIPY-based molecular rotors gained a lot of attention, as they turn on their fluorescence in response to the changes in viscosity and offer a high sensitivity tool to map the viscosity within biomolecules and lipid membranes .…”

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

“…All the derivatives exhibited reversible one-electron reduction waves and the irreversible oxidation ones, except for 4a. Upon installing the TIPS-ethynyl substituents into the BODIPY core, the reduction potentials are significantly shifted in the anodic direction rather than the extent of the shifts in the oxidation potentials [30]. The electron-deficient effect of the substituents is pronounced for the doubly substituted derivatives 4a and 6a.…”

“…For the applications mentioned above, various BODIPY dyes functionalized at the meso-, α-, and β-pyrrolic positions have been extensively developed to tune the optoelectronic properties [21]. Therefore, the development of more efficient and shorter step synthetic methods for the BODIPY derivatives, such as direct C-H functionalizations (e.g., arylation [22][23][24][25][26][27][28], annulation [29], olefination [30], styrylation [31], and borylation [32]), has been in great demand recently rather than the conventional multistep synthesis with nucleophilic substitution/cross-coupling via halogenation of BODIPYs [33] or from the activated precursors [34] via unstable pyrrolic intermediates. In particular, halogenation (e.g., bromination) of BODIPY derivatives often affords a mixture of multiply halogenated products, which is tedious to separate by column chromatography.…”

Pd-Catalyzed Intermolecular Dehydrogenative Heck Reactions of Five-Membered Heteroarenes

“…Pd II -catalyzed DHRs of boron dipyrromethene derivatives were carried out with either styrenes and AgOAc [75] or acrylates and AgOCOCF3 (Equation 38 Pd II -catalyzed DHRs of boron dipyrromethene derivatives were carried out with either styrenes and AgOAc [75] or acrylates and AgOCOCF 3 (Equation (38)) [76], affording dyes with improved properties. Pd II -catalyzed DHRs of boron dipyrromethene derivatives were carried out with either styrenes and AgOAc [75] or acrylates and AgOCOCF3 (Equation (38)) [76], affording dyes with improved properties. (38)…”

“…Interestingly, selective C5-olefination also occurred from 4chlorothiazole, 2-methylthiazole, and unsubstituted thiazole (Equation (77)). (76) 76Catalysts 2020, 10, x FOR PEER REVIEW 31 of 49 (77) The key intermediates proposed by Maiti's team for the template reactions are depicted in Scheme 16 [112]. Exchange between acetonitrile and thiazole provides 16A.…”