Aryne chemistry. Part XVIII. Some reactions of tetrahalogenobenzynes with styrene and substituted styrenes

Abstract

Tetrachlorobenzyne and tetrafluorobenzyne react with styrene to yield predominantly or exclusively 1,2,3,4-tetrahalogeno-9,10-dihydrophenanthrenes or 1,2,3,4-tetrahalogenophenanthrenes in good yield. Similar reactions are reported in which the arynes were generated in the presence of α-methyl-, trans-β-methyl-, 2-methyl-, 3-methyl-, 4-methyl-, and 2,4-dimethyl-styrene. Reactions were also carried out with trans-stilbene, 1,1-diphenylethylene, 1-phenylcyclohexene, and 1-vinylnaphthalene. The mechanism of formation of 1,2,3,4-tetrafluoro-9,10-dihydrophenanthrene has been studied by use of suitably deuteriated compounds. A discussion of the mechanism of formation of 1,2,3,4-tetrafluorophenanthrene, and of 9,10-dihydro-9-phenylphenanthrene in the reaction of benzyne with styrene, is based on reactions with deuteriated styrenes.