Water‐Dependent Selective Synthesis of Mono‐ or Bis‐Selanyl Alkenes from Terminal Alkynes

Abstract

Abstract We described here an alternative method for the selective synthesis of mono‐ or bis‐selanyl alkenes. This method involves reactions of terminal alkynes with organylselenols, generated in situ by the reaction of diorganyl diselenides with H 3 PO 2 . These reactions proceeded efficiently at 90 °C under N 2 atmosphere and are suitable to a range of diorganyl diselenides and terminal alkynes, both containing electron‐withdrawing and electron‐donating groups, affording the corresponding mono‐ or bis‐selanyl alkenes in good yields and selectively. When the reactions were performed using 5.0 equiv. of H 3 PO 2 (0.5 mL; 50 wt% in H 2 O), mono‐selanyl alkenes were formed in good yields, whereas reactions carried out with additional H 2 O as the solvent (3.0 mL/mmol) provided bis‐selanyl alkenes in high yields. Additionally, the solvent/reducing agent system (H 2 O/H 3 PO 2 ) could be recovered and directly reused for further reactions to synthesize bis‐selanyl alkenes.