Highly Diastereo- and Enantioselective Organocatalyzed Michael/Oxa-Michael Sequence: Asymmetric Synthesis of Pyranonaphthoquinone Derivatives
作者:Yong Hwan Kim、Subin Jang、Dae Young Kim
DOI:10.1002/bkcs.11566
日期:2018.10
synthesis of pyranonaphthoquinones via Michael addition and oxo‐Michael cyclization sequence of 2‐hydroxy‐1,4‐naphthoquinone with (E)‐2‐nitroallylic acetates has been developed. The synthetically useful chiral pyranonaphthoquinone derivatives were obtained in moderate to high yields and high enantioselectivities. This approach offers a facile way to prepare chiral pyranonaphthoquinone derivatives with
An NHC-catalyzed Michael/Michael/esterification domino reaction via homoenolate/enolate intermediates for the asymmetric synthesis of tetrasubstituted cyclopentanes bearing four contiguous stereocenters is described. A variety of [small alpha],[small beta]-unsaturated aldehydes and 2-nitroallylic acetates react...
描述了通过NHC催化的经由均烯酸酯/烯酸酯中间体的Michael / Michael /酯化多米诺反应,用于不对称合成带有四个连续立体中心的四取代环戊烷。各种[小α],[小β]-不饱和醛与2-硝基烯丙基乙酸酯反应...
Cinchona Squaramide‐Catalyzed Intermolecular Desymmetrization of 1,3‐Diketones Leading to Chiral 1,4‐Dihydropyridines
作者:Maciej Dajek、Agnieszka Pruszczyńska、Krzysztof A. Konieczny、Rafał Kowalczyk
DOI:10.1002/adsc.202000455
日期:2020.9.8
Addition of prochiral cyclic 1,3‐diketones to Michael acceptors applying bifunctional Cinchona‐derived squaramides resulted in chiral adducts with stereoselectivities of up to 99% ee and allowed for desymmetrization of the nucleophile. These labile hemiacetal intermediates were transformed to new 1,4‐dihydropyridines with high diastereoselectivities and no erosion of optical purity. Their further oxidation
An efficient method has been successfully developed to achieve the asymmetric C–H functionalization of indoles in the carbocyclic ring via organocatalysis, and a variety of tetrahydropyranoindoles were synthesized in good yields with excellent stereoselectivities. Further study on thermodynamic calculations indicated that the process was promoted by generating more thermodynamically stable products
An Organocatalytic Asymmetric Tandem Reaction for the Construction of Bicyclic Skeletons
作者:Chun-Li Cao、You-Yun Zhou、Jian Zhou、Xiu-Li Sun、Yong Tang、Yu-Xue Li、Guang-Yu Li、Jie Sun
DOI:10.1002/chem.200900696
日期:2009.10.26
the presence of catalytic pyrrolidine‐thiourea, which affords bicyclicskeletons with four or five stereocenters in one single reaction with up to 98 % ee in moderate to high yields. The cooperative effects of both enamine and the Brønsted acid are found to be crucial for the high reactivity and enantioselectivity of this cascade reaction, which is demonstrated by both theoretical calculation and experimental