Two‐Step Synthesis of Unsymmetrical Diaryl Sulfides by Electrophilic Thiolation of Non‐functionalized (Hetero)arenes

Abstract

This article reports the efficient preparation of a series of unsymmetrically substituted thioethers through a two‐step procedure consisting of an initial metal‐free C−H sulfenylation of electron‐rich (hetero)arenes with newly prepared succinylthioimidazolium salts. Subsequent reaction of the arylthioimidazolium intermediates with Grignard reagents afford the desired thioethers. The synthetic protocol described is modular, scalable, and high yielding, and provides access to sulfides that are not easy to obtain through the existing methodologies. Importantly, no prefunctionalization of the initial (hetero)arene is required.

Tris(4-methoxyphenyl)stibine

“…To our surprise, the structure of the title compound ( Fig. 1) is not reported in the database (CSD; Groom et al, 2016), although we regularly observe it as a side product in our synthesis of asymmetric sulfides (Bö hm et al, 2018). To fill the gap in the row of homologues of the type C 21 H 21 O 3 E, with E being an element of group 14, the title compound is reported herein.…”

Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

“…Böhm and co‐workers [212] have reported the transition metal‐free, double sulfenylation of nucleophiles by two‐step procedure which yielded unsymmetrical disulfides ( 317 ). Firstly, metal‐free C−H sulfenylation of electron rich molecule yielded aryl succinylthioimidazolium salts ( 316 ), followed by nucleophilic attack of Grignard reagent on it resulted into unsymmetrical disulfides ( 317 ).…”

“…Grignard reagent was used to displace carbene moiety from arylthioimidazolium salts, which is otherwise not achieved with soft organozinc reagents. It is noteworthy to mention here that Grignard reagent prepared following Knochel condition partially allows the accommodation of additional functional groups [212] …”

“…4-Nitrobenzoate chloride substituted thioether (213) were obtained when three membered cyclic thioether were used as substrates. However, utilizing four-membered thioether as substrates resulted into a mixture of chloro and 4-nitrobenzoate substituted products (212,213).…”

A Unified Strategy for Arylsulfur(VI) Fluorides from Aryl Halides: Access to Ar‐SOF3 Compounds

“…Moreover, the method should be facile, robust and with a high degree of functional group tolerance. Inspired by previous work on electrophilic sulfur reagents [17] and after a survey of various candidates (e.g. Bunte salts, [18] Ar-S-S(O) 2 Ph [19] or Ar-S-CN [20] ), N-(arylsulfenyl)phthalimides (Ar-S-Phth) attracted our attention due to their thermal stability upon storage despite the weak S À N bond.…”