Metacyclophanes and Related Compounds. 4. Halogenations of 8,16-Dialkyl-anti-5,13-di-tert-butylmetacyclophan-1-enes and 2,7-Di-tert-butyl-trans-10b,10c-dihydropyrenes

Article abstract of DOI:10.1021/ja00377a027

8,16-Dialkyl-anti-5,13-di-tert-butyl<2.2>metacyclophan-1-enes (13) and 2,7-di-tert-butyl-trans-10b,10c-dialkyl10b,10c-dihydropyrenes (20 a-c) wereprepared from the corresponding alkylbenzenes in several steps.The bromination of 13 and 20 with bromine in a carbon tetrachloride solution afforded 2,7-di-tert-butyl-4,5,9,10-tetrabromo-trans-10b,10c-dialkyl-10b,10c-dihydropyrenes (2).Treatment of 20 with iodine in a boiling benzene solution gave the dealkylated compound, 2,7-di-tert-butylpyrene (28).Such dealkylation was also observed in the bromination of 20 with bromine in the presence of Fe powder.However, without Fe powder, the bromination of 20 did not give any products.It was also found that the chlorination of 13a and 20a with iodine chloride of chlorine afforded the further chlorinated 2,7-di-tert-butyl-2,4,5,9,10-hexachloro-trans-10b,10c-dimethyl-2,7,10b,10c-tetrahydropyrene (30).The reaction pathways of the halogenation of the titled compounds are also discussed.