Probing the Mechanism of Allylic Substitution of Morita–Baylis–Hillman Acetates (MBHAs) by using the Silyl Phosphonite Paradigm: Scope and Applications of a Versatile Transformation
作者:Maria Kalyva、Alexandros L. Zografos、Era Kapourani、Evaggelos Giambazolias、Laurent Devel、Athanasios Papakyriakou、Vincent Dive、Yannis G. Lazarou、Dimitris Georgiadis
DOI:10.1002/chem.201405626
日期:2015.2.16
using 31P NMR spectroscopy revealed unexpected reactivity differences between ester and nitrile derivatives. These kinetic profiles and DFT calculations support a mechanistic scenario in which observed differences can be explained from the “lateness” of transition states. In addition, we provide experimental evidence suggesting that enolates due to initial P‐Michael addition are not formed. Based on
AP 甲硅烷基膦酸酯和森田-的Baylis-希尔曼乙酸盐(MBHAs)之间C键形成反应探索作为向医药相关β-carboxyphosphinic结构基序的通用的替代方案。使用31记录的不同取代的MBHA转化为次膦酸9或14的转化率P NMR光谱显示酯和腈衍生物之间的反应性差异出乎意料。这些动力学曲线和DFT计算支持了一种机械方案,其中可以从过渡态的“迟缓”解释观察到的差异。此外,我们提供的实验证据表明,由于最初的P-Michael加成而形成的烯醇不形成。基于拟议的机械情景结合DFT计算,对E / Z的解释提出了酯和腈之间的立体选择性差异。提出了由这种转变产生的合成机会,该机会涉及几种合成的反复变化的膦基结构单元的制备,而这些结构单元通过经典的P-Michael合成路线的访问并不简单。