A study of the chemistry of some polyfluoroaromatic prop-2-ynyl ethers and prop-2-enyl thioethers

Abstract

This work involves vapour phase and solution-phase studies of several polyfluoroaromatic prop-2-ynyl ethers and prop-2-enyl thio- ethers. When the prop-2-enyl thioether has a hydrogen ortho to the sulphur then a conventional thio-Claisen rearrangement occurs. However, if there are fluorine substitutents ortho to the sulphur then rearrangement to an ortho-dienethione is followed by hemolysis of the carbon to fluorine bond of the carbon to which the prop-2-enyl group has migrated. Claisen rearrangement followed by homolytic cleavage of the carbon to fluorine bond of the carbon to which the prop-2-ynyl group migrates occurs for the prop-2-ynyl ethers, which have fluorine substitutents ortho to the oxygen. The thesis is divided into six main parts. Chapter one deals with the literature on the Claisen and thio-Claisen rearrangements including the mechanistic development of the Claisen rearrangement. Chapters two and three are concerned with the thermal reactions of pentafluorophenyl, 2,3,4,5-tetrafluorophenyl, and 2,3,5,6-tetra- fluorophenyl prop-2-enyl thioethers. Chapter four describes attempted syntheses of the compounds arising out of the reaction of pentafluorophenyl prop-2-enyl thioether in N,N-diethylani1ine .Chapters five and six discuss the thermal chemistry of pentafluorophenyl and 1,3,4,5,6,7,8-heptafluoro-2-naphthyl prop-2-ynyl ethers.The thesis ends with a general conclusion tying together the work on the prop-2-enyl thioethers with that on the prop-2-ynyl ethers.