Stereoselective Synthesis of Racemic and Optically Active <i>E</i>-Vinyl and <i>E</i>-Dienyl Sulfoxides via Wittig Reaction of α-Sulfinyl Phosphonium Ylides
A series of ol-sulfinyl phosphonium ylides have been obtained in the reaction of phosphonium mono- and diylides with sulfinic acid esters. The use of(-)-(S)-menthyl-p-toluenesulfinate in this reaction afforded the corresponding (S)-((p-tolylsulfinyl)methyl)triphenylphosphonium ylide. The Wittig reaction of these ylides with saturated and unsaturated aldehydes resulted in the formation of racemic and optically active (+)-(R)-vinyl and dienyl sulfoxides with the E-geometry. The synthesis of (+)-(R)-((p-tolylsulfinyl)methyl)triphenyl iodide as a precursor of the optically active ylide has also been described.
Metal-free, one-pot highly selective synthesis of (E)-vinyl sulfones and sulfoxides via addition–oxidation of thiols with alkynes
We have developed a highlyselectiveone-pot method for the synthesis of (E)-vinyl sulfones and sulfoxides from thiols with terminal alkynes. The sulfones and sulfoxides could be obtained with excellent selectivity in good isolated yields. It is simple, efficient and environmentally benign, and metal-free. The mechanism for the formation of the (E)-vinyl sulfones was also proposed.