Organocatalytic Asymmetric Cascade Michael-acyl Transfer Reaction between 2-Fluoro-1,3-diketones and Unsaturated Thiazolones: Access to Fluorinated 4-Acyloxy Thiazoles
作者:Rayhan G. Biswas、Sumit K. Ray、Rajshekhar A. Unhale、Vinod K. Singh
DOI:10.1021/acs.orglett.1c02313
日期:2021.8.20
Quinine derivedbifunctional urea catalyzed cascade Michael-acyl transfer reaction of 5-alkenyl thiazolones and monofluorinated β-diketones has been developed. The fluorine containing 4-acyloxy thiazoles were synthesized in high yields and good diastereo-and excellent enantioselectivities. Synthetic transformations, including synthesis of 4-hydroxy thiazoles, have been demonstrated.
Oxidative N-heterocyclic carbene catalyzed stereoselective annulation of simple aldehydes and 5-alkenyl thiazolones
作者:Li Lin、Yuhong Yang、Mei Wang、Luhao Lai、Yarong Guo、Rui Wang
DOI:10.1039/c5cc01587a
日期:——
A highly stereoselective annulation proceeded successfully to afford chiral thiazolo pyrones with excellent ee (up to 99%) and d.r. (up to >20 : 1). Both enantiomers can be obtained. In the presence of oxygen (O2), the oxidant O-1 can be used in a catalytic amount (even low to 2 mol%).
Bifunctional Squaramide‐Catalysed Asymmetric Michael/Hemiketalization/Retro‐Aldol Reaction of Unsaturated Thiazolones with α‐Nitroketones: Synthesis of Chiral 4‐Acyloxythiazole Derivatives
作者:Yong‐Xing Song、Da‐Ming Du
DOI:10.1002/adsc.201900901
日期:2019.11.5
An efficient and practical organocatalytic asymmetric cascade Michael/hemiketalization/retro‐aldolreaction of unsaturated thiazolones with α‐nitroketones by using cyclohexanediamine‐derived bifunctional squaramide as the catalyst has been developed. Under mild conditions, a broad range of chiral 4‐acyloxythiazole derivatives were obtained in high yields (up to 98% yield) with excellent enantioselectivities
Asymmetric synthesis of spirooxindole-fused spirothiazolones<i>via</i>squaramide-catalysed reaction of 3-chlorooxindoles with 5-alkenyl thiazolones
作者:Yong-Xing Song、Da-Ming Du
DOI:10.1039/c9ob00998a
日期:——
An efficient and practical organocatalyzed asymmetric formal [2 + 1] cycloaddition of 3-chlorooxindoles with 5-alkenyl thiazolones by using hydroquinine-derived squaramide as the catalyst has been developed. Under mild conditions, a broad range of spirooxindole-fused spirothiazolones bearing three adjacent stereogenic centers including two vicinal spiro quaternary chiral centers were obtained in high
Catalyst-Controlled Diastereoselectivity Switch in the Asymmetric [3 + 2] Annulation of Isatin-Derived MBH Carbonates and 5-Alkenylthiazol-4(5<i>H</i>)-ones
作者:Ming-Shun Mei、Ya-Jie Wang、Gui-Shan Zhang、Jing-Yi Tang、Ping Tian、Yu-Hui Wang
DOI:10.1021/acs.orglett.1c02421
日期:2021.10.1
Exploration of the diastereodivergent synthesis of spirocyclic oxindoles has been challenging. Herein we report asymmetric [3 + 2] annulations of isatin-derived Morita–Baylis–Hillman (MBH) carbonates and 5-alkenylthiazol-4(5H)-ones. Interestingly, two different chiral catalysts, amide-phosphine and 4-dimethylaminopyridine (DMAP)-thiourea, could lead to two kinds of diastereomeric dispiro oxindoles