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
Ruthenium-Catalyzed Dynamic Kinetic Resolution Asymmetric Transfer Hydrogenation of β-Chromanones by an Elimination-Induced Racemization Mechanism
作者:Eric R. Ashley、Edward C. Sherer、Barbara Pio、Robert K. Orr、Rebecca T. Ruck
DOI:10.1021/acscatal.6b03191
日期:2017.2.3
compounds is an important goal. Ruthenium-catalyzed asymmetric transferhydrogenation under strongly basic conditions has been found to induce dynamic kineticresolution of β-substituted chromanones, producing valuable chromanols in high yields and with high levels of stereocontrol. The reaction proceeds by base-catalyzed racemization of the β-stereocenter through a conjugate elimination/conjugate
Metal-free oxidative decarbonylative alkylation of chromones using aliphatic aldehydes
作者:Rongzhen Chen、Jin-Tao Yu、Jiang Cheng
DOI:10.1039/c8ob00720a
日期:——
A decarbonylative alkylation of chromones via radical conjugate addition under metal-free conditions was developed using aliphaticaldehydes as alkylating reagents. A series of 2-tertiary, secondary, and even primary alkylated chromanones were obtained in moderate to excellent yields.
Harmonization of an incompatible aqueous aldol condensation/oxa-Michael addition/reduction cascade process over a core–shell-structured thermoresponsive catalyst
作者:Yu Su、Chengyi Wang、Qipeng Chen、Yuanli Zhu、Shaomin Deng、Shoujin Yang、Ronghua Jin、Guohua Liu
DOI:10.1039/d3gc01670f
日期:——
site-isolated bifunctional catalyst. This catalyst features thermoresponsive poly(N-isopropylmethacrylamide) with a switching function via a reversible transition between its hydrogel and solution phases that perfectly matches a temperature-tuned base-catalyzed aldol condensation/oxa-Michael addition at 70 °C and the ruthenium-catalyzed dynamic kinetic resolution asymmetric transfer hydrogenation (DKR-ATH)
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