Cesium Hydroxide Promoted Stereoselective Synthesis Of (Z)-1, 2-bis-chalcogenide(S, Se) Alkenes

Cesium hydroxide is an inorganic superior base, it can respoil the proton of weak acids organic(such as ArSH,ArSeH) to form the corresponding carbon or hetero anions. Cesium cation has big cation radius and small electrostatic with anion, which make anions proforms strong nucleophilicity. They can react smoothly with many reagents at room temperature, which will effectively prevent the competition of the heat reaction. (Z)- bis-chalcogenide(S,Se) alkenes are important intermediates in organic synthesis, the reported methods of synthesizing (Z)- bis-chalcogenide(S,Se) alkenes in the literature exist currently a lot of shortage, some use expensive Palladium (Pd) reagents;some need strict anaerobic waterless operations; some of the products are the mixture of the Z and E-isomers, poor stereoselectivity; some damand the reacrion was proceeded at high temperature in the refluxed EtOH, as the temperature is too high, there is often the competition of side reacrions. Therefore, in accordance with the principle of cesium cation activing the anion , We researched in the presence of a catalytic amount of cesium hrdroxide to Synthesize a series of (Z)- bis-chalcogenide(S,Se) alkenes, the main research works are as follows:(1) We studied in the presence of a catalytic amount of cesium hrdroxide that ArSeH is proceeded the Nucleophilic addition to Alkynyl selenides to give the high stereo- and regioselective symmetry, asymmetry of the target products of (Z) -1,2-dis(arylseleno)alkenes, yield 87%～98%, stereoisomer is established through NOE spectra. our approach has its own advantages: atom economy, readily available staring materials, mild reaction conditions, no need for strictly anaerobic and waterless operations, simple reaction and workup procedures, high yields and specific products, etc.(2) We studied in the presence of a catalytic amount of cesium hrdroxide that ArSH is proceeded the Nucleophilic addition to deferent substituted Alkynyl sulfides to give the high stereo- and regioselective symmetry, asymmetry of the target products of (Z) -1,2-dis(arylthio)alkenes, product-specific, no other by-products generated, yield 87%～98%, stereoisomer is established through NOESY spectra.(3) Different chalcogenide(S,Se)-substituted alkenes is an important intermediate in organic synthesis, we studied in the presence of a catalytic amount of cesium hrdroxide that ArSH is proceeded the Nucleophilic addition to Alkynyl selenides to give the high stereo- and regioselective specific products of (Z)-1-arylseleno-2-arylthio alkenes, yield 70%～97%, for the synthesis of different chalcogenide-substituted alkenes provides a new method.