Development of Tartaric Acid Derived Chiral Guanidines and Their Application to Catalytic Enantioselective α-Hydroxylation of β-Dicarbonyl Compounds
摘要:
A novel library of chiral guanidines featuring a tartaric acid skeleton was developed from diethyl L-tartrate. These guanidines are easily accessed with tunable style and electronic properties. The utilities of the guanidines were highlighted by their ability to catalyze the alpha-hydroxylation of beta-ketoesters and beta-diketones with remarkable efficiency and excellent enantioselectivity.
Novel tartrate-derived guanidine-catalyzed highly enantio- and diastereoselective Michael addition of 3-substituted oxindoles to nitroolefins
作者:Liwei Zou、Xiaoze Bao、Yuanyuan Ma、Yuming Song、Jingping Qu、Baomin Wang
DOI:10.1039/c4cc01817f
日期:——
The Michael addition of 3-substituted oxindoles to nitroolefins was catalyzed by a novel tartrate-derived guanidine in high yield with excellent diastereo- and enantioselectivity. This method showed an extraordinarily broad substrate scope in terms of both reaction partners.
Novel Tartrate-Based Guanidines for Enantioselective Fluorination of 1,3-Dicarbonyl and α-Cyano Carbonyl Compounds
作者:Liwei Zou、Xiaoze Bao、Huanrui Zhang、Yuming Song、Jingping Qu、Baomin Wang
DOI:10.1071/ch14179
日期:——
electronic properties. A guanidine molecule of this library with an incorporated 2,6-diisoaniline fragment was identified as a suitable promoter for the enantioselective fluorination of 1,3-dicarbonyl and α-cyano carbonyl compounds to furnish the fluorinated product with up to 84 % ee and 99 % yield using N-fluorobenzenesulfonimide (NFSI) as the fluorinating agent.
An Organocatalytic Asymmetric Friedel–Crafts Addition/Fluorination Sequence: Construction of Oxindole–Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters
作者:Xiaoze Bao、Baomin Wang、Longchen Cui、Guodong Zhu、Yuli He、Jingping Qu、Yuming Song
DOI:10.1021/acs.orglett.5b02470
日期:2015.11.6
A highly efficient and practical one-pot sequential process, consisting of an organocatalytic enantioselective Friedel–Crafts-type addition of 4-nonsubstituted pyrazolones to isatin-derived N-Boc ketimines and a subsequent diastereoselective fluorination of the pyrazolone moiety, is developed. This reaction sequence delivers novel oxindole–pyrazolone adducts featuring vicinal tetrasubstituted stereocenters