Direct Photoexcitable Iodomethylborate Enabling Cyclopropanation of Reactive Alkenes

Nakamura, Rikako; Sumida, Yuto; Ohmiya, Hirohisa

doi:10.1246/bcsj.20220112

Cited by 5 publications

(1 citation statement)

References 27 publications

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“…We recently designed direct excitable borates in which the carbon–boron bond undergoes homolysis under photoirradiation. ,− The photoexcitable borates used in our laboratory undergo a single-electron transfer in the excited state, resulting in the generation of a C(sp 3 ) radical and carbon–boron (C–B) bond cleavage (Figure b). We envisioned that the previously developed iodomethyl borate would allow formal methylation of the betaine nitrogen atoms, resulting in the construction of an N -methyl caged molecule (caging methylation). Betaine is a structural motif frequently found in pharmacologically active compounds that act on the nervous system and are thus important targets for caged chemistry .…”

Section: Introductionmentioning

confidence: 99%

Radical Caging Strategy for Cholinergic Optopharmacology

et al. 2023

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Photo-caged methodologies have been indispensable for elucidating the functional mechanisms of pharmacologically active molecules at the cellular level. A photo-triggered removable unit enables control of the photo-induced expression of pharmacologically active molecular function, resulting in a rapid increase in the concentration of the bioactive compound near the target cell. However, caging the target bioactive compound generally requires specific heteroatom-based functional groups, limiting the types of molecular structures that can be caged. We have developed an unprecedented methodology for caging/uncaging on carbon atoms using a unit with a photo-cleavable carbon−boron bond. The caging/uncaging process requires installation of the CH 2 −B group on the nitrogen atom that formally assembles an N-methyl group protected with a photoremovable unit. N-Methylation proceeds by photoirradiation via carbon-centered radical generation. Using this radical caging strategy to cage previously uncageable bioactive molecules, we have photocaged molecules with no general labeling sites, including acetylcholine, an endogenous neurotransmitter. Caged acetylcholine provides an unconventional tool for optopharmacology to clarify neuronal mechanisms on the basis of photo-regulating acetylcholine localization. We demonstrated the utility of this probe by monitoring uncaging in HEK cells expressing a biosensor to detect ACh on the cell surface, as well as Ca 2+ imaging in Drosophila brain cells (ex vivo).

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Section: Introductionmentioning

confidence: 99%

Radical Caging Strategy for Cholinergic Optopharmacology

et al. 2023

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Radical C‐Glycosylation Using Photoexcitable Unprotected Glycosyl Borate

Miyamoto,

Murakami,

Sumida

et al. 2024

Chemistry A European J

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We have developed radical C‐glycosylation using photoexcitable unprotected glycosyl borate. The direct excitation of glycosyl borate under visible light irradiation enabled the generation of anomeric radical without any photoredox catalysts. The in situ generated anomeric radical was applicable to the radical addition such as Giese‐type addition and Minisci‐type reaction to introduce alkyl and heteroaryl groups at the anomeric position. In addition, the radical–radical coupling between the glycosyl borate and acyl imidazolide provided unprotected acyl C‐glycosides.

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