CS 2 /KOH System-Promoted Stereoselective Synthesis of ( E )-Alkenes from Diarylalkynes and a "Hidden" Zinin-Type Reduction of Nitroarenes into Arylamines.

In this work, we present the CS 2 /KOH system as a practical and efficient reductive medium for obtaining ( E )-alkenes from alkynes through a highly stereoselective semireduction reaction. This cost-effective system enabled successful semireduction reactions of diverse alkynes using water as a hydrogen source, yielding moderate to excellent yields. The versatility of this protocol is further demonstrated through the synthesis of relevant compounds such as pinosylvin and resveratrol precursors, along with the notable anticancer agent DMU-212. Furthermore, during the reaction scope investigation, we serendipitously disclosed that this reductive system was also able to promote a Zinin-type reaction to reduce nitroarenes into arylamines.