利用刺激响应水凝胶作为双功能催化剂进行水相连续有机转化制备手性有机分子不仅对环境友好,而且弥补了相互矛盾的多步反应的合成局限性。然而,找到解决顺序转换中复杂的多组件交叉相互作用所引起的不兼容问题的解决方案是一项重大挑战。为了解决这个问题,我们开发了一种核壳结构水凝胶作为位点隔离的双功能催化剂。该催化剂具有热响应性聚(N-异丙基甲基丙烯酰胺),具有开关功能水凝胶和溶液相之间的可逆转变,完美匹配 70 °C 下的温度调节碱催化羟醛缩合/氧杂迈克尔加成反应和 40 °C 下钌催化的动态动力学拆分不对称转移氢化 (DKR-ATH) 过程C 正如我们所设想的,通过协调冲突的顺序反应,这种羟醛缩合/oxa-Michael加成/DKR-ATH级联过程可以通过从不相容到相容的转变来实现,从而能够直接获得具有1,3位的手性苯并二氢吡喃醇。来自市售正交的双立体中心-羟基芳基酮和醛。机理研究包括监测级联反应和分
Metal-Free Oxidative C(sp<sup>3</sup>)–H Bond Functionalization of Alkanes and Conjugate Addition to Chromones
作者:Jincan Zhao、Hong Fang、Ping Qian、Jianlin Han、Yi Pan
DOI:10.1021/ol502524d
日期:2014.10.17
A metal-free oxidative C(sp3)–H bond functionalization and subsequent conjugate addition reaction using di-tert-butyl peroxide (DTBP) as the oxidant was established, which tolerates a wide range of simple alkane substrates to react with different substituted chromones for direct preparation of 2-alkylchromanones.
Catalytic asymmetric conjugate addition of Grignard reagents to chromones
作者:Carlos Vila、Valentín Hornillos、Martín Fañanás-Mastral、Ben L. Feringa
DOI:10.1039/c3cc43105c
日期:——
highly regio- and enantioselective copper catalysed direct conjugateaddition of Grignard reagents to chromones has been developed taking advantage of the reduced reactivity of the resulting magnesium enolates. This methodology tolerates a broad scope of alkyl Grignards including secondary alkyl magnesium reagents as well as functionalised chromones.
A new synthetic approach for 2-alkylchromanones utilizing Fe (III)-catalyzed reductive cross-coupling of olefins with chromones has been developed. The reaction conditions are mild, and various substituted alkenes are applicable to the process. Moreover, control experiments were conducted, and a plausible mechanism is proposed.
已经开发了一种利用 Fe (III) 催化烯烃与色酮的还原交叉偶联的 2-烷基色酮的新合成方法。反应条件温和,可适用多种取代烯烃。此外,还进行了控制实验,并提出了一个合理的机制。
Tin-free radical reactions under minimal solvent conditions for the synthesis of substituted chromones and coumarins
作者:Jake R. Zimmerman、Madhuri Manpadi、Russell Spatney
DOI:10.1039/c1gc15775b
日期:——
An alkyltin-free radical methodology carried out under minimal solvent conditions is presented. This free radical addition process allows for the preparation of a variety of substrates, including substituted chromones and coumarins. This method is high yielding, conducted at ambient temperature and, in nearly all instances, classical purification techniques such as chromatography are not needed.
Synthesis of 2-alkyl-chroman-4-ones <i>via</i> cascade alkylation–dechlorination of 3-chlorochromones
作者:Shunyao Li、Lanfei Zhang、Qian He、Xiaofei Zhang、Chunhao Yang
DOI:10.1039/d1ob00463h
日期:——
An efficient and mild synthetic approach for 2-alkyl-substituted chroman-4-ones via zinc mediated cascade decarboxylative β-alkylation and dechlorination of 3-chlorochromones was developed.