Regio-and stereocontrolled synthesis of (Z)-α-(phenylseleno)sulfinyl and-sulfonyl alkenes via sulfenic acids, and a study of their reactivity

Article abstract of DOI:10.1002/ejoc.201100759

A general procedure for the synthesis of α-(phenylseleno)sulfinyl and-sulfonyl alkenes has been described. 1-(Phenylseleno)ethenyl sulfoxides were prepared by the syn-addition of in situ-generated sulfenic acids on to the triple bond of suitably substituted (phenylseleno)acetylenes. 1-(Phenylseleninyl)ethenyl sulfones were obtained by further oxidation of their sulfinyl analogues. The mild conditions of the sulfenic acid/(phenylseleno) alkyne syn-addition and its stereospecificity and regioselectivity allowed us to obtain electron-poor alkenes with a well defined stereochemistry and sensitive substituents at the double bond. Chiral (Z)-1-[(2,3,4,6-tetra-O-acetyl-β-D- glucopyranosyl)sulfinyl]-1-(phenylseleno)-1-hexene was also obtained via the enantiopure2,3,4,6-tetra-O-acetylglucosulfenic acid. The reactivity of α-(phenylseleninyl)sulfinyl and-sulfonyl alkenes has been evaluated in nucleophilic additions to the electron-poor double bond, conducted with hard nucleophiles such as piperidine and phenol.