Hetero-Diels–Alder Reactions of Quinone Methides: The Origin of the α-Regioselectivity of 3-Methylene-1,2,4-naphthotriones
作者:Maicon Delarmelina、Sabrina B. Ferreira、Fernando de C. da Silva、Vitor F. Ferreira、José Walkimar de M. Carneiro
DOI:10.1021/acs.joc.0c00215
日期:2020.6.5
previously reported for other quinone methide intermediates are also observed for 3-methylene-1,2,4-naphthotriones, such as small endo/exo diastereoselectivity, as well as pronounced ortho/meta regioselectivity for reactions performed with dienophile containing electron-releasing groups. The results presented here provide a deeper understanding of the reactivity of quinone methide derivatives, aiding the
通过实验和计算方法研究了通过异狄尔斯-阿尔德反应的α-和β-拉帕酮的区域选择性形成。详细探讨了实验观察到的α-选择性,发现与β-异构体相比,形成α-lapachone的较低能垒是整个反应路径中较低的Pauli排斥力的结果。根据活化应变模型(ASM)和能量分解分析(EDA),通过比较α-和β-拉帕酮势能面(PES)上的等效点,我们能够证明Pauli排斥项在从反应物要TS β比TS α,导致反应路径早期和β-拉帕酮的过渡态反应能降低。此外,我们证实先前针对其他醌甲基化物中间体报道,区域选择性和非对映选择性的趋势也为3-亚甲基-1,2,4- naphthotriones,如小观察到内切/外切非对映选择性,以及显着的邻位/间位与含有电子释放基团的亲二烯体进行的反应的区域选择性。此处提供的结果提供了对醌甲基化物衍生物反应性的更深入的理解,有助于未来反应条件的合理设计,可能的醌甲基化物中间体的结构