Sulfenylation of C–H Bonds for C–S Bond Formation under Metal‐Free Conditions

Abstract

Sulfenylation of C–H bonds for C–S bond formation under metal‐free conditions has become established as a powerful tool in organic chemistry. Various sulfenylation reagents such as thiols, disulfides, sulfinic acids, and so on have been employed for sulfenynlation reactions. In this review we mainly summarize the recent advances (2014 to the present) in this area and also discuss the mechanisms.

Divergence in Ynone Reactivity: Atypical Cyclization by 3,4‐Difunctionalization versus Rare Bis(cyclization)

“…Interestingly, the formation of bis(triflyl)thioflavone (3a)w as observed (Scheme 2) rather than Friedel-Crafts-type bis(triflyl)alkylation or cyclobutenec onstruction( Scheme 1). Notably,aC À Sb ond, [6] which is present in av ast array of naturalp roducts and bioactive molecules,s uch as thioflavones, was formed under mild conditions. The organofluorine substituent was also incorporated in the same step under metal-free conditions through dual functionalization of the alkynem oiety.W ith these cyclization conditions in hand, we examined the scope of MeS-functionalized ynones that were susceptible to thioflavone generation.…”

Synthesis of Thioethers from Sulfonyl Chlorides, Sodium Sulfinates, and Sulfonyl Hydrazides

“…Since 2011, S 8 , 11 CS 2 , 12 KSCN, 13 DMSO, 14 NaS 2 O 3 , 15 thiourea, 16 Bunte salts, 17 potassium O-ethyl dithiocarbonate, 18 and N-(aryl/alkylsulfanyl)succinimides, 19 etc., have all been employed as sulfur sources for the synthesis of sulfides, however, most of these sources provide only a single sulfur atom. Sulfur sources, such as thiols, 20,21 disulfides, 22 sulfonyl chlorides, 10,20, and sodium sulfinates 25,29,[44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] and sulfonyl hydrazides have also been employed in the synthesis of sulfides, with the desired products being obtained in good yields. These protocols greatly enrich existing synthetic routes, and they may provide an alternative to traditionally used methodologies in some cases.…”

Sulfonylation of Benzylic C−H Bonds through the Reaction of Aryl(o‐tolyl)methanones with Sulfonyl Hydrazides or Sulfonyl Chlorides

“…[1] In addition, the sulfonyl unit is often used as av ersatile motif in organic synthesis. [2] Thus, significante ffort has been devoted to the construction of sulfone compounds. Traditionally,s ulfone derivatives were synthesized throught he nucleophilic substitution of carbon electrophiles with thiols [3] or disulfides [4] and subsequento xidation.…”