Carbene‐Catalyzed Enantioselective Aromatic N‐Nucleophilic Addition of Heteroarenes to Ketones
作者:Yonggui Liu、Guoyong Luo、Xing Yang、Shichun Jiang、Wei Xue、Yonggui Robin Chi、Zhichao Jin
DOI:10.1002/anie.201912160
日期:2020.1.2
and optical purities. Our reaction involves the formation of an unprecedented aza-fulvene-type acylazolium intermediate. A broad range of N-heteroaromatic aldehydes and electron-deficient ketone substrates works effectively in this transformation. Several of the chiral N,O-acetal products afforded through this protocol exhibit excellent antibacterial activities against Ralstonia solanacearum (Rs) and
Nucleophilic β-Carbon Activation of Propionic Acid as a 3-Carbon Synthon by Carbene Organocatalysis
作者:Zhichao Jin、Ke Jiang、Zhenqian Fu、Jaume Torres、Pengcheng Zheng、Song Yang、Bao-An Song、Yonggui Robin Chi
DOI:10.1002/chem.201501481
日期:2015.6.22
Direct β‐carbonactivation of propionic acid (C2H5CO2H) by carbene organocatalysis has been developed. This activation affords the smallest azolium homoenolate intermediate (without any substituent) as a 3‐carbon nucleophile for enantioselective reactions. Propionic acid is an excellent raw material because it is cheap, stable, and safe. This approach provides a much better solution to azolium homoenolate
已经开发了通过卡宾有机催化作用对丙酸(C 2 H 5 CO 2 H)进行直接β-碳活化。这种活化提供了最小的均氮唑鎓中间体(无任何取代基),作为对映选择性反应的3碳亲核试剂。丙酸是便宜,稳定和安全的原料,因此是一种极好的原料。这种方法比以前建立的丙烯醛(没有任何取代基的烯醛)使用昂贵,不稳定且有毒的方法提供了更好的解决方案,用于合成均氮唑鎓。
Carbene‐Catalyzed Enantioselective Aldol Reaction: Post‐Aldol Stereochemistry Control and Formation of Quaternary Stereogenic Centers
作者:Xing Yang、Pankaj Kumar Majhi、Huifang Chai、Bin Liu、Jun Sun、Ting Liu、Yonggui Liu、Liejin Zhou、Jun Xu、Jiawei Liu、Dongdong Wang、Yanli Zhao、Zhichao Jin、Yonggui Robin Chi
DOI:10.1002/anie.202008369
日期:2021.1.4
The dominated approaches for asymmetric aldol reactions have primarily focused on the aldol carbon–carbon bond‐forming events. Here we postulate and develop a new catalytic strategy that seeks to modulate the reaction thermodynamics and control the product enantioselectivities via post‐aldol processes. Specifically, an NHC catalyst is used to activate a masked enolate substrate (vinyl carbonate) to
DBU-Mediated Diastereoselective Aldol-Type Cyanomethylation of Isatins
作者:V. U. Bhaskara Rao、Krishna Kumar、Tamal Das、Kumar Vanka、Ravi P. Singh
DOI:10.1021/acs.joc.7b00512
日期:2017.4.21
diastereoselectivity. Further transformation of the cyanide group allowed the synthesis of an advance intermediate of corresponding (±) CPC analogue. The mechanistic insight toward the aldol-type cyanomethylation of N-tritylisatin with benzyl cyanide was obtained by DFT calculations.
Acetylphosphonate as a Surrogate of Acetate or Acetamide in Organocatalyzed Enantioselective Aldol Reactions
作者:Jie Guang、Qunsheng Guo、John Cong-Gui Zhao
DOI:10.1021/ol301270w
日期:2012.6.15
Highly enantioselective aldol reactions of acetylphosphonates and activated carbonyl compounds was realized with cinchona alkaloid derived catalysts, in which the acetylphosphonate was directly used as an enolate precursor for the first time. The aldol product obtained was converted in situ to its corresponding ester or amide through methanolysis or aminolysis. The overall process may be viewed as formal highly enantioselective acetate or acetamide aldol reactions, which are very difficult to achieve directly with organocatalytic methods.