Photoinduced deconstruction of cycloalkanols for site-selective sulfonylsulfination

Abstract

A facile methodology of photo-enabled deconstructive sulfonylsulfination of cycloalkanols is reported, providing a direct access to valuable ketones bearing β-sulfonyl sultine moiety with S IV and S VI centers under mild and sustainable conditions with broad functional-group tolerance. Mechanistic investigations suggest a PCET-mediated deconstructive process and a radical-polar crossover cyclization pathway involving double SO2 insertion in this transformation.Alkoxy radicals are highly transient species that readily undergo β-scission process to crack the adjacent C-C bond, thereby generating more stable carbon-centered radicals. 1 Owing to this inherent reactivity, this specific transformation has been extensively explored in a variety of elegant approaches toward valuable molecules, particularly for the deconstructive functionalization of cycloalkanols for kinds of functionalized ketones. 2 Despite the high dissociation energy of free alcohols (BDFE of RO-H bond ≈ 105 kcal/mol), the direct homolytic activation of O-H bond for the generation of alkoxy radicals remains the most straightforward strategy. As a consequence, transition-metal-catalyzed methods enabling alkoxy radical formation have been established, generally requiring chemical oxidants and being mainly applicable to strained cycloalkanols. 3 Very recently, environmentally benign photocatalysis and 2