Cornforth–Evans Transition States in Stereocontrolled Allylborations of Epoxy Aldehydes
作者:Robert R. A. Freund、Matthias Borg、Daniel Gaissmaier、Robin Schlosser、Timo Jacob、Hans‐Dieter Arndt
DOI:10.1002/chem.202001479
日期:2020.7.14
(CE) model for alkoxy‐ and epoxy‐substituted aldehydes. CE‐type transition states were uniformly identified as minima in advanced, DFT‐based computational studies of allylboration reactions of epoxy aldehydes, conforming well to the experimental data, and highlighting the underestimated relevance of this model. Furthermore, a mechanism‐based rationale for the substitution pattern of the epoxide was delineated
烯丙基硼化反应是有机合成中最可靠的工具之一。在本文中,我们报告了三官能化的烯丙基硼酸酯的一般合成方法,以及对它们与取代的醛底物的立体控制转化的系统研究,以便有效地访问各种高度取代的目标底物。对于极性烷氧基和环氧取代的醛,从极性Felkin-Anh(PFA)到Cornforth-Evans(CE)模型观察到立体控制有一个奇特的过渡。在基于DFT的环氧醛烯丙基硼化反应的高级计算研究中,CE型过渡态被统一确定为极小值,与实验数据吻合良好,并突出了该模型的低估相关性。此外,