Room-Temperature Synthesis of Tetrasubstituted 1,3-Dithioles by Dimerizing Sulfuration of Chalcones with Elemental Sulfur

Sulfur-Promoted Oxidative Cyclization of Pentan-1-ones: Direct Access to Tetrasubstituted Furans from Deoxybenzoins and Chalcones

Furan is an important heterocyclic scaffold in natural product, bioorganic, and medicinal chemistry as well as in materials science. The system S8/DABCO/DMSO was found to efficiently mediate the oxidative cyclization of 1,2,3,5-tetraarylpentan-1-ones A, which were obtained in situ as the Michael adducts of chalcones 1 and deoxybenzoins 2, to furan 3. The strategy provided convenient and direct access to tetrasubstituted furans 3 from readily available starting materials with high functional group tolerance.

Sulfur-Promoted Oxidative Condensation of Chalcones with Unsubstituted Cyanoacetamide in DMSO: Access to 3-Cyanopyrid-2-ones

Elemental sulfur and DABCO were found to be an excellent combination to promote a one-pot cascade of condensation-oxidative cyclization of chalcones and unsubstituted cyanoacetamide in DMSO to provide 3-cyanopyrid-2-ones.

Base-Promoted Reaction of 4-Chloro-3-vinyl Coumarins, Phenacylpyridinium Bromides, and Elemental Sulfur: A Designed Approach to Thiopyrano[4,3-c]chromen-5(1H)-ones

A designed synthesis of thiopyrano[4,3-c]chromen-5(1H)-ones was developed based on a base-promoted three-component reaction between 4-chloro-3-vinyl coumarins, phenacylpyridinium bromides, and elemental sulfur. Readily available starting materials, mild conditions, chemoselectivity, operational simplicity, and synthetically useful yields are some highlighted advantages of these transformations.

A stepwise one-pot synthesis of aliphatic thiols and their derivatives from acrylamides and sulfur

Elemental sulfur enables the convenient formation of C-S bonds and the direct incoporation of S-S bonds. The reactivity of easily accessible electron deficient alkenes towards sulfur, however, is barely disclosed. Herein, we investigated the reactivity of acrylamides with sulfur and eventually developed a new pseudo-multicomponent reaction for the preparation of polysulfides. Sequential one-pot reduction led to diversely substituted thiols. Additional third stage one-pot modifications provided thioethers, unsymmetric disulfide and thioester.

Convenient Synthesis of Triphenylphosphine Sulfide from Sulfur and Triphenylphosphine

Elemental sulfur (S8) was found to react very rapidly (<1 min) with a stoichiometric amount of triphenylphosphine at rt in sufficient amount of solvent (0.2–0.5 mL of solvent/1 mmol of PPh3). Compared to the previously described methods, the present procedure constitute excellent access to triphenylphosphine sulfide.

Base-Catalyzed Three-Component Reaction between Chalcones, Isothiocyanates, and Sulfur: Access to Thiazole-2-thiones

A convenient synthesis of thiazole-2-thiones was developed based on base-catalyzed three-component reactions between chalcones, isothiocyanates, and elemental sulfur.