Recent Advances in Sulfur-Containing Heterocycle Formation via Direct C–H Sulfuration with Elemental Sulfur

Abstract

The synthesis of sulfur heterocycles via the construction of C–S bonds has received considerable attention due to their biological value and extensive pharmaceutical application. While diverse sulfurating agents have been developed over the past few decades, in this regard, elemental sulfur, with advantages of low toxicity, odorless nature and chemical stability, has great potential for the construction of diverse sulfur heterocycles through its direct incorporation into the target molecules in a concise way. Direct functionalization of inert C–H bonds can shorten the number of reaction steps and minimize the amount of waste formed. Hence, heteroannulations via direct C–H sulfuration is considered to be an attractive strategy for the synthesis of sulfur heterocycles. In the last few years, a vast array of concise systems have been reported for the synthesis of some valuable sulfur heterocycles such as thiophenes, thienoindoles, thienothiazoles, thiazoles, benzothiazoles, and thiadiazoles through direct C–H sulfuration/annulations with elemental sulfur. These are discussed in detail in this review.1 Introduction2 Thiophenes3 Thienoindoles4 Thienothiazoles5 Other Fused Thiophenes6 Thiazoles7 Benzothiazoles8 Thiadiazoles9 Others10 Summary and Outlook

Iodine and DMSO as Surrogate of Hazardous Metal and Non‐Metal Reagents in Organic Synthesis

“…Sulfidation of aromatic compounds via CÀ H activation to obtain biologically active species, [119][120][121][122] has gained significant attention. [123][124][125][126][127] However, there are only a handful of reports for sulfidation of perfluoroarenes; [128][129][130][131][132] in which the metal catalysts like palladium chloride (Scheme 11 (a)) [133] and high amounts of bases like KOH (Scheme 11 (c)) [134] have been used with diphenylsulphane to incorporate the sulphur containing fragment in the target motifs.…”

Recent Advances in the Synthesis of Isothiocyanates Using Elemental Sulfur

“…The most common activation of sulfur is the cleavage of the octasulfur ring by nucleophiles [42][43][44][45][80][81][82]. Generally, cyanide, hydroxyl and sulfide ions may homolytically (Scheme 11A) or heterolytically (Scheme 11B) cleave sulfur-sulfur bonds under mild conditions, generating reactive linear polysulfide anion chains of different lengths (50) and radical anions (51) [83,84].…”

Recent Advances in the Synthesis of Sulfides, Sulfoxides and Sulfones via C-S Bond Construction from Non-Halide Substrates

“…Elemental sulfur is an attractive sulfur source for the construction of C-S bond due to the low toxicity, stability, ready availability, odorless, and economical price [52]. In 2018, the Adimurthy group reported a copper catalyzed C-H disulfenylation of imidazo[1,2-a]pyridine for the synthesis of diaryl sulfides.…”