Controllable Sulfoxidation and Sulfenylation with Organic Thiosulfate Salts via Dual Electron- and Energy-Transfer Photocatalysis

Abstract

Sulfoxides and sulfides are two important functional groups in organic molecules, containing different valence states of sulfur. Both sulfoxidation and sulfenylation with common sulfurating reagents were successfully tuned via a facile variation of the atmosphere under photocatalyzed conditions. The sulfoxidation and sulfenylation transformations involved tandem electron-/energy-transfer and single-electron-transfer processes, respectively. Late-stage sulfoxidation for pharmaceuticals and sugar derivatives was established to be highly compatible. Divergent formal syntheses of sulfoxide/sulfide-containing marketed pharmaceuticals were switchably implemented. Gram-scale operations further demonstrated the practicability of the protocol.

Construction of 4‐(Methylthio)isochromenones Skeleton through Regioselective Intramolecular Cyclization of 2‐Alkynylbenzoate Mediated by DMSO/[D6]DMSO and SOCl2

“…Meanwhile, diverse substituents can be introduced at the 4‐position of the isochromenones , . Although C sp 2 –S bond formation had been widely reported, the preparation of 4‐sulfenylisochromenones has been less explored due to the limitation on their synthetic strategies. Larock and co‐workers reported that by treating alkynes with the electrophilic sulfenyl chloride, sulfoesterification occurred to give the corresponding 4‐(sulfenyl)isochromenones (Scheme a).…”

Sulfur‐Center‐Involved Photocatalyzed Reactions

“…In 2017, our group achieved controllable sulfoxidation and sulfenylation with thiosulfate salts and aryl iodoniums by using Eosin Y as a cheap catalyst and adjusting the atmosphere [Eq. (115)] . Late‐stage sulfoxidation of pharmaceuticals and sugar derivatives was established with high compatibility.…”

“…(115)]. [81] Late-stage sulfoxidation of pharmaceuticalsa nd sugar derivatives was established with high compatibility.D ivergent formal syntheses of sulfoxide/sulfide-containing marketed pharmaceuticals were implemented. Gram-scale operations further demonstrated the practicality of the protocol.…”

Iodine(III) Enabled Dehydrogenative Aryl C−S Coupling by in situ Generated Sulfenium Ion

“…[4] For many years, synthesis of CÀS bonds [5] were usually based on the transition metal catalyzed cross couplings [6] of aryl halides with thiophenols. [11] However, among metal free methods, [12] most of the coupling reactions are reported via prefunctionalization of the substrates. [8] Similarly, Ni, Co, Pd, or Cu metal catalyzed coupling reactions of aryl halides or template assisted synthesis are described in Figure 1a and Figure 1b, respectively.…”

“…[9] Aryl sulfenylation [10] and sulfoxidation under photocatalytic condition have also recently been developed but the method contains drawback such as use of thiosulfate salts. [11] However, among metal free methods, [12] most of the coupling reactions are reported via prefunctionalization of the substrates. [13] Therefore, dehydrogenative coupling reactions via non-requirement of prefunctionalized substrates are mostly desirable, for example our present approach is shown in Figure 1c.…”