Asymmetric Organocatalytic Formal [2 + 2]-Cycloadditions via Bifunctional H-Bond Directing Dienamine Catalysis
作者:Łukasz Albrecht、Gustav Dickmeiss、Fabio Cruz Acosta、Carles Rodríguez-Escrich、Rebecca L. Davis、Karl Anker Jørgensen
DOI:10.1021/ja211878x
日期:2012.2.8
concept in organocatalysis allowing for the construction of cyclobutanes with four contiguous stereocenters with complete diastereo- and enantiomeric control by a formal [2 + 2]-cycloaddition is presented. The concept is based on simultaneous dual activation of α,β-unsaturated aldehydes and nitroolefins by amino- and hydrogen-bonding catalysis, respectively. A new bifunctional squaramide-based aminocatalyst
有机催化中的一个新概念允许构建具有四个连续立体中心的环丁烷,通过正式的 [2 + 2]-环加成实现完全非对映和对映体控制。该概念基于分别通过氨基和氢键催化同时双重活化 α,β-不饱和醛和硝基烯烃。为了实现这种活化策略,已经设计并合成了一种新的基于双功能方酰胺的氨基催化剂。证明了反应的潜力和范围,并提出了解释立体化学结果的计算研究。