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

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.

Practical synthesis of unsymmetrical disulfides promoted by bromodimethylsulfonium bromide

Oxidative cross-coupling of two thiols is the most direct tool for the synthesis of unsymmetrical disulfides and highly desirable across academia and industry. However, the inevitable formation of significant amounts of the corresponding symmetrical by-products is a major issue. We herein present a method toward the synthesis of unsymmetrical disulfides in which the homo-coupling of the thiols is effectively inhibited by adding the two thiols sequentially, taking advantage of rapid oxidation of the thiol by bromodimethylsulfonium bromide.

Regio- and Stereoselective Synthesis of β-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 β-methylthio vinyl triflates in a chemo-, regio-, and stereoselective manner under neutral and extremely simple conditions.