Base-Promoted Ring-Opening Hydroxylation of Cyclic Sulfonium Salts

Base-Free Synthesis of S-Alkyl Isothioureas Through Ring-Opening Reaction of Sulfonium Salts with Isothiocyanates and Amines

A convenient and base-free three-component reaction has been developed for the synthesis of S-alkyl substituted isothioureas from cyclic sulfonium salts, isothiocyanates, and amines. This protocol provides an alternative avenue to access a series of S-alkyl substituted isothioureas in moderate to good yields through ring-opening reaction of aryl, alkenyl and alkynyl sulfonium salts. The present strategy features operational simplicity, good functional group tolerance, gram-scale synthesis and high reaction efficiency.

Elemental Sulfur/Selenium-Mediated Metal-Free Phosphinothioation and Phosphinoselenoation of Vinylsulfonium Salts with P-H Bonds

An efficient and facile method has been developed for the construction of novel P-S-C and P-Se-C bonds by facilitating the three-component cross-coupling reaction of P-H bonds with elemental sulfur/selenium and vinylsulfonium salts, utilizing sodium bicarbonate as a base. This approach eliminates the need for the use of toxic and odorous active sulfur/selenium reagents and noble metals, thereby offering a new pathway for synthesizing S-phosphinothioates and Se-phosphinoselenoates via the organic conversion of inorganic sources. The reaction has showcased remarkable versatility in terms of substrate applicability, particularly for organophosphorus compounds containing P-H bonds and vinylsulfonium salt derivatives. The resulting phosphinothioation/phosphinoselenoation products can be obtained with high yield and regioselectivity. Additionally, a plausible reaction mechanism for this transformation has been proposed based on step-by-step control experiments and 31P NMR tracking analysis.

Pnictogen and Chalcogen Salts as Alkylating Agents

Alkylation reactions and their products are considered crucial in various contexts. Synthetically, the alkylation of a nucleophile is usually promoted using hazardous alkyl halides. Here, we aim to highlight the potential of pnictogen (ammonium or phosphonium) and chalcogen salts (sulfonium, selenonium, and telluronium) to function as alkylating agents. These compounds can be considered as non-volatile electrophilic alkyl reservoirs. We will center our discussion on the strategies developed in recent years to expand the synthetic utility of these salts in terms of transferable alkyl groups, substrate scope, and product selectivity.

Synthesis of S-Alkyl Dithiocarbamates via Multicomponent Reaction of Cyclic Sulfonium Salts with CS2 and Amines

A convenient and practical method for the synthesis of various S-alkyl dithiocarbamates through three-component reaction of sulfonium salts, CS2 and amines has been developed. The reaction proceeds efficiently without any catalyst and additive under mild and open-air conditions, making it potential applications in pharmaceutical chemistry and sulfur chemistry.

Ring-Opening Sulfonylation of Cyclic Sulfonium Salts with Sodium Sulfinates under Transition-Metal- and Additive-Free Conditions

Incorporating a sulfonyl group into parent molecules has been shown to effectively improve their synthetic applications and bioactivities. In this study, we present a straightforward and practical approach for the ring-opening reaction of alkenyl-aryl sulfonium salts with sodium sulfinates to produce a range of sulfur-containing alkyl sulfones. This method offers the benefits of mild reaction conditions, easily accessible raw materials, wide substrate applicability, good functional group compatibility, and operational simplicity. Importantly, the resulting products can be readily converted into sulfoxides, sulfones, sulfoximines, and some heterocyclic compounds.

Synthesis of alkynyl sulfides via base-promoted nucleophilic ring-opening of α-bromostyrene sulfonium salt

An efficient method for the synthesis of alkynyl sulfides via a C(sp3)-S bond cleavage of α-bromostyrene sulfonium salts has been developed. This base-promoted nucleophilic ring-opening pathway allows the preparation of diverse alkynyl sulfide compounds using tetramethylene sulfoxide as the sulfur source. The reaction proceeds with good functional group tolerance and could be applied to the late-stage functionalization of bioactive molecules and drugs. Furthermore, the synthetic utility of this method was demonstrated by a one-pot synthesis, scale-up reaction and further modification of various alkynyl sulfide products.