Stereochemistry of the Conversion of γ-Substituted (E)-Vinylsulfones to the Corresponding Allylsulfones. Determination of the Relative Degree of “Syn-Effect”
Convenient Methods for the Preparation of Vinylic and Allylic Sulfones from Alkenes, Haloalkanes, and Aldehydes. Stereochemistry of the Conversion of Vinylic Sulfones to the Corresponding Allylic Sulfones
1- or 2-p-Tolylsulfonyl(=tosyl)-1-alkenes, vinylic sulfones, were regioselectively prepared from 1-alkenes via iodosulfonization or sulfonylmercuration and also from 1-haloalkanes by the homologati...
2-p-Toluenesulfonyl(=tosyl)-1-alkenes were regioselectively prepared from 1-alkenes via iodosulfonization or sulfonylmercuration, respectively. Conversion of 1-tosyl-1-alkenes to the corresponding allylic sulfones, 1-tosyl-2-alkenes, was achieved by the treatment of their acetonitrile solution with DBU in high yield.
(E)-2-Iodo-1-tosyl-1-alkenes readily available by iodosulfonization of 1-alkynes were found to be useful synthons for the regio- and/or stereoselective preparation of 1-tosyl-1-alkynes, 1-tosyl-2-alkynes, (Z)-vinyl and (Z)-allyl sulfones, β-tosyl enamines, α-tosyl ketones, α-tosyl aldehyde acetal, and β-disubstituted vinyl sulfones.
Several (E)- and (Z)-1-p-toluenesulfonyl(=tosyl)-2-alkenes, allylsulfones, were regio- and stereoselectively prepared from aldehydes and alkynes, respectively, in good yields by application of the results of our previous investigation on “syn-effect” and iodosulfonization.