Photochemical difluoromethylation of alkynes: synthesis of CF₂H-substituted seven-membered dioxodibenzothiazepines and dibenzazepines

Abstract

A general and efficient photochemical strategy for the difluoromethylation/radical cascade cyclization of alkynes with sodium difluoromethylsulfinate (NaSO2CF2H) has been disclosed. This system provides a straightforward access to diverse pharmaceutically appealing...

Cu-Electrocatalysis Enables Vicinal Bis(difluoromethylation) of Alkenes: Unraveling Dichotomous Role of Zn(CF2H)2(DMPU)2 as Both Radical and Anion Source

“…We then were curious whether the conventionally utilized CF 2 H radical sources could solely mediate the desired transformation. However, Zn(SO 2 CF 2 H) 2 , NaSO 2 CF 2 H and TMSCF 2 H, which were previously employed in radical difluoromethylative functionalizations, ,,− were ineffective for the vicinal bis(difluoromethylation) while giving rise to the exclusive formation of 3a ′ (Figure E). These results highlight that both radical and anionic CF 2 H sources are necessary for the desired reactivity, and 2 is capable of fulfilling both roles within this newly established Cu-electrocatalytic system.…”

Visible light-induced organophotoredox-catalyzed difunctionalization of alkenes and alkynes

“…Dioxodibenzothiazepine and their derivatives are an important class of N -heterocycles showing emerging interests as they widely exist in biologically active molecules and sulfonamide drug molecule. 32 Very recently (2023), Zhu, Wu, & Wu et al 33 developed an efficient method for the difluoromethylation of alkynes with the help of the photochemical reaction. The authors demonstrated that N -(2-ethynylphenyl)- N ,4-dimethylbenzenesulfonamid ( 16a ) reacted with sodium difluoromethylsulfinate ( 16b ) in the presence of 5 mol% photocatalyst eosin Y to afford the desired difluoromethylated dioxodibenzothiazepine ( 16c ) with up to 74% yield and excellent stereo-selectivity E / Z ratio of 97 : 3 (Scheme 16).…”