四川大学冯小明团队首次实现了乙烯基环氧化合物Meinwald重排引发的不对称催化乙烯基加成反应。 相关研究成果于2021年4月7日发表在国际知名学术期刊《德国应用化学》。

研究人员采用手性N，N′-二氧化物/Sc（III）络合物催化剂，首次实现了乙烯基环氧化合物Meinwald重排引发的不对称多乙烯基加成反应。乙烯基环氧化合物作为β，γ-不饱和醛的掩蔽物，通过与靛蓝、2-烯基吡啶或亚甲基吲哚酮的直接乙烯基加成反应，分别为合成手性3-羟基-3-取代的羟吲哚、α，β-不饱和醛和螺环己烯吲哚酮提供了一种简便有效的方法，且该方法具有高的效率和立体选择性。

控制实验和动力学研究表明，Lewis酸作为双任务催化剂，控制初始重排以匹配随后的对映选择性乙烯基加成反应。同时提出了一个具有可能的过渡模型的催化循环来说明反应机理。

附：英文原文

Title: Asymmetric Catalytic Vinylogous Addition Reactions Initiated by Meinwald Rearrangement of Vinyl Epoxides

Author: Jinxiu Xu, Yanji Song, Jun He, Shunxi Dong, Lili Lin, Xiaoming Feng

Issue&Volume: 2021-04-07

Abstract: The first catalytic asymmetric multiple vinylogous addition reactions initiated by Meinwald rearrangement of vinyl epoxides were realized by employing chiral N,N′‐dioxide/Sc(III) complex catalysts. The vinyl epoxides, as masked β,γ‐unsaturated aldehydes, via direct vinylogous additions with isatins, 2‐alkenoylpyridines or methyleneindolinones, provided a facile and efficient way for the synthesis of chiral 3‐hydroxy‐3‐substituted oxindoles, α,β‐unsaturated aldehydes and spiro‐cyclohexene indolinones, respectively with high efficiency and stereoselectivity. The control experiments and kinetic studies revealed that the Lewis acid acted as dual‐tasking catalyst, controlling the initial rearrangement to match subsequent enantioselective vinylogous addition reactions. A catalytic cycle with a possible transition model was proposed to illustrate the reaction mechanism.

DOI: 10.1002/anie.202102054

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202102054