Vermeeren Pascal, Hamlin Trevor A, Fernández Israel, Bickelhaupt F Matthias
Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081, HV, Amsterdam, The Netherlands.
Departamento de Química Orgánica I and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
Angew Chem Int Ed Engl. 2020 Apr 6;59(15):6201-6206. doi: 10.1002/anie.201914582. Epub 2020 Feb 19.
The Lewis acid(LA)-catalyzed Diels-Alder reaction between isoprene and methyl acrylate was investigated quantum chemically using a combined density functional theory and coupled-cluster theory approach. Computed activation energies systematically decrease as the strength of the LA increases along the series I <SnCl <TiCl <ZnCl <BF <AlCl . Emerging from our activation strain and Kohn-Sham molecular orbital bonding analysis was an unprecedented finding, namely that the LAs accelerate the Diels-Alder reaction by a diminished Pauli repulsion between the π-electron systems of the diene and dienophile. Our results oppose the widely accepted view that LAs catalyze the Diels-Alder reaction by enhancing the donor-acceptor [HOMO -LUMO ] interaction and constitute a novel physical mechanism for this indispensable textbook organic reaction.
采用密度泛函理论和耦合簇理论相结合的方法，对路易斯酸（LA）催化异戊二烯与丙烯酸甲酯之间的狄尔斯-阿尔德反应进行了量子化学研究。随着路易斯酸强度沿着I＜SnCl＜TiCl＜ZnCl＜BF＜AlCl系列增加，计算得到的活化能系统地降低。从我们的活化应变和科恩-沙姆分子轨道键合分析中出现了一个前所未有的发现，即路易斯酸通过减少二烯和亲双烯体的π电子系统之间的泡利排斥来加速狄尔斯-阿尔德反应。我们的结果与广泛接受的观点相反，即路易斯酸通过增强供体-受体[HOMO-LUMO]相互作用来催化狄尔斯-阿尔德反应，并为这一不可或缺的教科书有机反应构成了一种新的物理机制。
