Recent Developments in C−S, C−Se Bond Formation via Three‐Component Reactions of Alkynes

Alkynes are valuable building blocks in organic synthesis. They can undergo three‐component difunctionalization to create sulfur or selenium‐containing compounds. Three‐component reactions of alkynes are atom economic, practical and regioselective. This review will disscuss decade developments, including C−S and C−Se bond formation via thiolation, sulfonylation and selenylation. Recent developments can be mainly categorized into three types. (1) Radical C−S/S−Se bond formation is a hot topic. Reactions initiated by S/Se radicals or other radicals exhibit two types of selectivities. Photochemical and electrochemical reactions under eco‐friendly conditions have been increasingly reported. (2) Some transformations involve electrophilic three‐membered ring intermediates. Thiiraniums, seleniraniums, and iodoniums are among the most prevalent species. They undergo ring‐opening by various nucleophiles and participate in tandem reactions. (3) Metal‐catalyzed reactions, a classic category, will also be discussed in the text. In the following section, we will provide an overview based on the mechanisms and substrates. The roles of added reagents will also be discussed. This review summarized C−S, C−Se bond formations via three‐component reactions of alkynes. Decade developments were categorized into three types, which include (1) C−S/C−Se bond formations using radical strategies; (2) Reactions triggered by three‐membered ring intermediates; (3) Reactions under metal‐catalyzed conditions and others. Mechanisms have been given for nearly all reactions.