Transition metal-free stereospecific di-chalcogenations of substituted acetylenes

We report a one-pot, transition metal-free, stereospecific di-chalcogenation reaction for the synthesis of a diverse range of substituted Z-di-organochalcogenides. This method employs Cs₂CO₃ as a non-toxic basic catalyst in dimethyl sulfoxide under mild conditions at 60 °C. The reaction proceeds with high stereospecificity, offering excellent functional group tolerance and high to excellent yields. The broad substrate scope, scalability to gram-level synthesis, and operational simplicity make the method highly practical and efficient. Intermediate 6aa' enabled the efficient synthesis of unsymmetrical (Z)-phenyl/aryl(1-phenyl-2-(phenylselanyl)vinyl)sulfane via coupling with diaryl diselenides in high yields. Additionally, the process features a clean reaction profile and is environmentally friendly, highlighting its potential for both academic and industrial applications. This approach provides a cost-effective and sustainable solution for Z-di-organochalcogenides synthesis.