Cycloaddition Reactions of 3-(Phenylthio)-3-buten-2-one: Synthesis of Functionalized Dihydropyran Derivatives and Their Ring-Opening Reactions

Article abstract of DOI:10.1021/jo00148a004

3-(Phenylthio)-3-buten-2-one (1) reacted with nucleophilic olefins such as vinyl ethers, vinyl sulfide, and enamine to give 1,4-cycloaddition products and/or Michael adducts 7-17 in fairly good yields.Treatment of 2-acetyl-2,5-bis(phenylthio)-3,4-dihydro-6-methyl-2H-pyran (2) with various acids or mercury(II) chloride gave the cyclopentanone 19.In addition, the dimer 2 was converted into 3-(phenylthio)-7-octene-2,6-dione (23) by the three steps.