Synthesis of Aryl Thioalkynes Enabled by Electrophilic Sulfenylation of Alkynes and the Following Elimination.

An unexpected deprotonative process of thiirenium ions is presented, which provides a new synthesis of aryl thioalkynes directly from terminal alkynes via the electrophilic activation of the carbon-carbon triple bonds. The conditions are well compatible with various functional-group-substituted aryl alkynes. The direct elimination from the thiirenium ion intermediate, or its tautomer, benzyl vinyl carbocation, is supported by control experiments and labeling reaction.

Synthesis of Pyrrole via Formal Cycloaddition of Allyl Ketone and Amine under Metal-Free Conditions.

A new metal-free synthesis of pyrrole from allyl ketone and amine has been established. The reaction proceeds via an thiolative activation of the C-C double bond with dimethyl(methylthio)sulfonium trifluoromethanesulfonate, followed by a nucleophilic ring-opening addition of primary amine to the generated episulfonium intermediate, and then an internal condensation and aromatization. This mild procedure provides a novel strategy to the construction of substituted pyrroles through a formal [4 + 1] cycloaddition reaction.

Photoinduced, Redox-Neutral Decyanative and Defluorinative Phosphination of (Hetero)Arenes.

Triarylphosphines play a crucial role in organic synthesis as versatile components serving as ligands, catalysts, and reactants. This study introduces a metal-free, visible-light-induced method for the cross-coupling of cyanopyridines or polyfluoroarenes with diarylphosphines. This approach facilitates the formation of C(sp2)-P bonds through redox-neutral decyanative or defluorinative process, enabling the convenient synthesis of diverse triarylphosphines.

Regio- and Stereoselective Synthesis of ß-Methylthio Vinyl Triflates.

Vinyl triflates are commonly employed as electrophilic vinyl sources in complex synthesis. The triflation of enolates is commonly required for the preparation of vinyl triflates, generally under strongly basic conditions. Herein, the reaction between alkynes and dimethyl(methylthio)sulfonium trifluoromethanesulfonate is presented, which leads to the development of a facile synthesis of ß-methylthio vinyl triflates in a chemo-, regio-, and stereoselective manner under neutral and extremely simple conditions.

Tandem utilization of CO2 photoreduction products for the carbonylation of aryl iodides.

Photocatalytic CO2 reduction reaction has been developed as an effective strategy to convert CO2 into reusable chemicals. However, the reduction products of this reaction are often of low utilization value. Herein, we effectively connect photocatalytic CO2 reduction and amino carbonylation reactions in series to reconvert inexpensive photoreduction product CO into value-added and easily isolated fine chemicals. In this tandem transformation system, we synthesize an efficient photocatalyst, NNU-55-Ni, which is transformed into nanosheets (NNU-55-Ni-NS) in situ to improve the photocatalytic CO2-to-CO activity significantly. After that, CO serving as reactant is further reconverted into organic molecules through the coupled carbonylation reactions. Especially in the carbonylation reaction of diethyltoluamide synthesis, CO conversion reaches up to 85%. Meanwhile, this tandem transformation also provides a simple and low-cost method for the 13C isotopically labeled organic molecules. This work represents an important and feasible pathway for the subsequent separation and application of CO2 photoreduction product.

Carbosulfenylation of Alkenes with Organozinc Reagents and Dimethyl(methylthio)sulfonium Trifluoromethanesulfonate.

The electrophilic alkylthiolation of alkenes, initiated by dimethyl(methylthio)sulfonium salts and the subsequent addition of various heteronucleophilies has been well-established. Regarding the use of carbon nucleophiles, however, only carefully designed sp-type carbon sources have been successfully applied. We herein present our findings on the methylthiolation of alkenes with dimethyl(methylthio)sulfonium trifluoromethanesulfonate, followed by carbon-carbon bond formation in the presence of organozinc reagents, thus achieving a catalyst-free protocol toward to the carbosulfenylation of alkenes.