Migratory aptitude of alkyl substituents in the MABR-promoted epoxide rearrangement
作者:Keiji Maruoka、Takashi Ooi、Hisashi Yamamoto
DOI:10.1016/0040-4020(92)85006-z
日期:1992.1
bis(4-bromo-2,6-di-tert-butylphenoxide) (MABR). With α,α-disubstituted epoxides, the organoaluminum-promoted epoxide rearrangement is interpreted for by proceeding with rigorous migration of hydride syn to the less hindered site of the epoxide ring, while the facile anti migration of the alkyl groups has been observed in tri- and tetrasubstituted epoxides. The selectivity observed in various types of
刘易斯酸促进的环氧化物重排的迁移能力已经用超大体积的路易斯酸性甲基铝双(4-溴-2,6-二叔丁基苯氧化物)(MABR)进行了研究。对于α,α-二取代的环氧化物,有机铝促进的环氧化物重排可通过将氢化物syn严格迁移至环氧化物环的受阻部位来进行解释,而在三元环烷基中观察到了烷基的抗迁移性和四取代的环氧化物。发现在各种类型的环氧化物中观察到的选择性远远优于其他普通路易斯酸,例如BF 3 ·OEt 2和SnCl 4。