Remarkable template effect of a Lewis acid receptor in the intramolecular radical cyclization: control of reaction pathway as well as stereochemistry
作者:Takashi Ooi、Yasutoshi Hokke、Eiji Tayama、Keiji Maruoka
DOI:10.1016/s0040-4020(00)01007-3
日期:2001.1
Abstract A remarkable template effect in the intramolecular radical cyclization process has been observed by the successful utilization of Lewis acid receptor, aluminum tris(2,6-diphenylphenoxide) (ATPH). The origin of this efficient template effect by ATPH would be ascribable to the well-defined reaction environment created in front of the aluminum coordination center; this enables appropriate proximity
摘要 通过路易斯酸受体三(2,6-二苯酚)铝(ATPH)的成功利用,观察到分子内自由基环化过程中的显着模板效应。ATPH 产生的这种有效模板效应可归因于在铝配位中心前创造的明确的反应环境;这使得初始产生的碳自由基与过渡态的不饱和碳-碳键适当接近,以实现平滑环化,因此完全抑制了不希望的分子间还原途径。此外,ATPH 独特的空腔提供的这种构象限制改变了环化的立体选择性。