Direct Transformation of Terminal Alkynes into Amidines by a Silver-Catalyzed Four-Component Reaction

An unprecedented conversion of terminal alkynes into N-sulfonimidamides (amidines) is reported by a silver-catalyzed, one-pot, four-component reaction with TMSN3, sodium sulfinate, and sulfonyl azide. The reaction scope includes both aromatic and aliphatic alkynes. A possible cascade reaction mechanism, consisting of alkyne hydroazidation, sulfonyl radical addition, 1,3-dipolar cycloaddition by TMSN3, and retro-1,3-dipolar cycloaddition, is proposed. TMSN3 is found to play an essential role in each step of the reaction.

本研究报道了一种前所未有的转化反应：通过银催化的一锅法四组分反应，以三甲基硅基叠氮（TMSN3）、亚磺酸钠与磺酰叠氮为反应物，实现末端炔烃向N-磺酰亚胺酰胺（脒）的转化。该反应的底物适用范围涵盖芳香族与脂肪族炔烃。研究提出了一种可能的级联反应机理，其依次包含炔烃氢叠氮化、磺酰自由基加成、三甲基硅基叠氮参与的1,3-偶极环加成以及逆1,3-偶极环加成步骤。研究发现三甲基硅基叠氮（TMSN3）在反应的各步骤中均发挥关键作用。