180136-95-2Relevant academic research and scientific papers
Reaction of [2.2]metacyclophanes having an internal C=C bond with brominating agents
Ishi-i, Tsutomu,Sawada, Tsuyoshi,Mataka, Shuntaro,Tashiro, Masashi
, p. 5103 - 5108 (2007/10/03)
Treatment of 5-tert-butyl-8-ethenyl[2.2]metacyclophane (2) with benzyltrimethylammonium tribromide or bromine exclusively gave the addition-elimination product, β-bromoolefin 6. The bromination reactions of (E)-5-tert-butyl-8-(2-phenylethenyl)[2.2]metacyclophane ((E)-3) and its isomer (Z)-3 were always stereoconvergent to give a mixture (40/60) of β-bromoolefins 8a and 8b, respectively. On the other hand, when (E)-8,8′-(ethene-l,2-diyl)bis(5-tert-butyl[2.2]metacyclophane) ((E)-4) and its isomer (Z)-4 were treated with the brominating agents, none of the products arising from the electrophilic attack of a bromonium ion on the central etheno bridge was obtained; the reaction of (E)-4 gave monotetrahydropyrene derivative 9 and bis(tetrahydropyrene) derivative 10, products resulting from a transannular reaction-alkenyl migration sequence. In the reaction of (Z)-4 the aromatic electrophilic substitution products 13-bromo compound 11 and 13,13′-dibromo compound 12 were obtained, along with a small amount of 9. The reaction pathway of the brominations mentioned above is discussed.
