Selective preparation. 30. A convenient preparation of 5,13-Di-tert-butyl-8,16-disubstituted-[2.2]metacyclophanes and their trans-tert-butylation and halogenation reactions
Selective preparation. 30. A convenient preparation of 5,13-Di-tert-butyl-8,16-disubstituted-[2.2]metacyclophanes and their trans-tert-butylation and halogenation reactions
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选择性准备。
DOI：
10.1021/jo00321a005
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发表时间：
1981
影响因子：
3.6
通讯作者：
T. Yamato
中科院分区：
文献类型：
--
作者：
M. Tashiro;T. Yamato
以相应的4-取代叔丁基苯为原料，制备了5,13 -二叔丁基- 8,16 -二取代-[2.2]元环蒽（16a-k）。由alcl3 - ch3n02催化的5,13 -二烷基丁基- 8,16 -二甲基[2.2]元环己烷（16b）在苯中的反式叔丁化反应得到8,16 -二甲基[2.2]元环己烷（28a），收率较高。然而，二乙基衍生物16c的类似反应只得到一个复杂的产物混合物。在CCI4中，NBS处理16b和28a可获得相应的二溴化物38和39，产量分别为86%和95%。在CC14中，16b和16c与溴的溴化反应得到相应的抗10b、10c-二烷基- 4,5,9,10 -四溴- 2,7 -二叔丁基-10b、10c-二氢芘41a和41b，产率较高。然而，也发现16b和16c在同一溶剂中在铁粉的存在下溴化，在所有情况下都能得到4,5,9,10 -四溴- 2,7 -二叔丁基芘（40）。另一方面，在铁粉存在下，28a与溴的溴化反应得到2,7 -二甲基- 3,6,8,11 -四溴- 4,5,9,10 -四氢芘（42）。讨论了16溴化的反应途径。
The preparation of 5, 13-di-tert-butyl-8, 16-disubtituted-[2.2] metacyclophanes (16a-k) from the corresponding 4-substituted-tert-butylbenzenes was described. The AlCl3-CH3N02-catalyzed trans-tert-butylation of 5, 13-di-ieri-butyl-8, 16-dimethyl [2.2] metacyclophane (16b) in benzene afforded 8, 16-dimethyl [2.2] metacyclophane (28a) in good yield. However, the similar reaction of diethyl derivative 16c gave only a complex mixture of products. Treatment of 16b and 28a with NBS in CCI4 afforded the corresponding dibromides 38 and 39 in 86% and 95% yields, respectively. The bromination of 16b and 16c with bromine in CC14 afforded the corresponding anti-10b, 10c-dialkyl-4, 5, 9, 10-tetrabromo-2, 7-di-tert-butyl-10b, 10c-dihydropyrenes 41a and 41b in good yields, respectively. However, it was also found that the brominationof 16b and 16c in the presence of Fe powder in the same solvent afforded 4, 5, 9, 10-tetrabromo-2, 7-di-tert-butylpyrene (40) in good yield in all cases. On the other hand, the bromination of 28a with bromine in the presence of Fe powder gave 2, 7-dimethyl-3, 6, 8, ll-tetrabromo-4, 5, 9, 10-tetrahydropyrene (42). The reaction pathway of the bromination of 16 is discussed.