Protocol for Visible-Light-Promoted Desulfonylation Reactions Utilizing Catalytic Benzimidazolium Aryloxide Betaines and Stoichiometric Hydride Donor Reagents

• DOI: 10.1021/acs.joc.0c00038
• Publication Date: 2020-02-19T14:37:30Z
• Authors: Eietsu Hasegawa; Tsukasa Tanaka; Norihiro Izumiya; Takehiro Kiuchi; Yuuki Ooe; Hajime Iwamoto; Shin-ya Takizawa; Shigeru Murata
• Keywords: Stoichiometry; Sulfonyl

An unprecedented photocatalytic system consisting of benzimidazolium aryloxide betaines (BI+-ArO-) and stoichiometric hydride reducing reagents was developed for carrying out desulfonylation reactions N-sulfonyl-indoles, -amides, -amines, α-sulfonyl ketones. Measurements absorption spectra cyclic voltammograms as well density functional theory (DFT) calculations were carried to gain mechanistic information. In the catalytic system, visible-light-activated benzimidazoline aryloxides (BIH-ArO-), generated in situ by reduction corresponding BI+-ArO-, donate both an electron a hydrogen atom substrates. A modified protocol also so that quantity more easily prepared hydroxyaryl benzimidazolines (BIH-ArOH) is used along with donor promote photochemical reactions.