ISOPRENE FUNCTIONALIZATION E/Z-ISOMERISM OF 1-SULFONYL SUBSTITUTED 2-METHYLBUTADIENES

Article abstract of DOI:10.1016/S0040-4020(01)93684-1

The isomeric chlorosulfones 3, 4 and 4 are prepared by 1,4-addition of sulfonyl chlorides to isoprene.Dehydrohalogenation affords the corresponding 2- and 3-methylbutadienyl sulfones in a configuration which is dependent on the configuration of the chlorosulfone.Pure Z-2-methylbutadienyl sulfones 1 are obtained by displacement of primary halides by the Z-sulfinate anion 2.The Z-sulfones 1 are isomerized to E/Z-mixtures.The E/Z-mixtures are separated into their components and the configuration of the isomers is established by the NMR-NOE technique.