Convergent and Functional-Group-Tolerant Synthesis of B-Organo BODIPYs

Abstract

Boron-dipyrromethenes (BODIPYs) are one of the most important fluorescent materials. Despite their potential unique properties, however, B,B-fluoro-organo BODIPYs (BFR-BODIPYs) possessing an organo group (R) on the boron center have not been studied in detail, due in part to challenges related to their synthesis. In this paper, a convergent synthesis of BFR-BODIPYs operative under mild conditions is reported. Conversions of the thus-synthesized functionalized BFR-BODIPYs by cross-coupling, condensation, and S N 2 reactions at the R group are also demonstrated.

Photophysical properties and application in live cell imaging of B,B-fluoro-perfluoroalkyl BODIPYs

“…Previously, we observed higher photostability of 2 than that of 1, which we verified by absorption spectrometry. 3 In the present study, the improved photostability of fluoro-perfluoroalkyl BODIPYs was confirmed using a photobleaching assay. Thus, when 1-3 dissolved in methanol were irradiated with a 500 nm light, the degradation rates of the fluorescence intensities of 2 and 3 were much slower than that of 1; 67%/47%/24% of 2 and 75%/59%/37% of 3 remained after irradiation for 15 min/30 min/60 min, respectively, while only 34%/11%/2% of 1 remained (Fig.…”

“…2.1 Synthesis of B,B-fluoro-perfluoroalkyl BODIPYs B,B-Fluoro-pentafluoroethyl BODIPY 3 was synthesized similarly to 2. 3 Thus, BF 2 C 2 F 5 was in situ generated by treating commercially available KijBF 3 C 2 F 5 ] with trimethylsilyl triflate in CH 3 CN and then added to a dichloromethane solution of tetramethyl dipyrromethene and ethyl diisopropyl amine (DIPEA). The coupling reaction was conducted at room temperature for 3 h, affording 3 in 23% isolated yield.…”

“…2 We recently disclosed a short and convergent synthesis of BFR-BODIPYs. 3 Because this method is operative under mild conditions, a variety of functionalized carbon substituents, whose introduction was difficult or unfeasible by previous methods, can be installed at the boron center. Specifically, B,B-fluoro trifluoromethyl BODIPY (2, Fig.…”

“…1) exhibits the most prominent photostability among various BFR-BODIPYs and BF 2 -BODIPYs. 3,4 Therefore, we studied the photophysical properties of B,B-fluoro perfluoroalkyl BODIPYs (2 and 3) and their potential usefulness in biologic research.…”

Convenient Preparation and Structure Determination of Air‐ and Moisture‐Tolerant Difluoromethylborates

“…[7] The BODIPY derivative C would be useful as a fluorescent material. [8] The boron 1,3-diketonate D works as a biocompatible oxidation catalyst of amyloid peptide under near-infrared light irradiation. [9] On the other hand, examples of the difluoromethylsubstituted borate derivatives have been limited so far.…”