Alkatrienyl sulfoxides and sulfones. Part II. [1] (5-methyl-1,3,4-hexatriene-3-yl) phenyl sulfoxide-synthesis and electrophile-promoted cyclization reactions

A method for synthesis of the (5-methyl-1,3,4-hexatriene-3-yl) phenyl sulfoxide 3 by [2,3]-sigmatropic rearrangement of the (5-methyl-1-hexene-3-yn-5-yl) benzenesulfenate 2 , formed in the reaction of the 5-methyl-1-hexene-3-yn-5-ol 1 with phenylsulfenyl chloride has been created. Five-membered heterocyclizations in electrophile-promoted reactions leading to the synthesis of the 5 H -1,2-oxathiol-2-ium salts and 3-(phenylsulfinyl)-thiophene or -selenophene have been explored. Halogenation of the sulfoxide 3 proceeded with formation of the 4-halo-5 H -1,2-oxathiol-2-ium halides 4 and 5 , while the reactions with phenylsulfenyl and phenylselenenyl chlorides afforded the mixtures of the 2-isopropyl-3-(phenylsulfinyl)-thiophene 6 or -selenophene 8 and 4-phenythio (seleno)-5 H -1,2-oxathiol-2-ium chlorides 7 and 9 .