Highly Diastereo- and Enantioselective Synthesis of α-Alkyl Norstatine Derivatives: Catalytic Asymmetric Mannich Reactions of 5H-Oxazol-4-ones
作者:Depeng Zhao、Linqing Wang、Dongxu Yang、Yixin Zhang、Rui Wang
DOI:10.1002/anie.201201804
日期:2012.7.23
Going Mannich: The title reaction results in the first catalyticasymmetricsynthesis of syn‐α‐alkyl norstatine derivatives. Excellent enantioselectivities and diastereoselectivities were achieved with a series of N‐diphenylphosphinoyl‐protected imines and 5H‐oxazol‐4‐ones by using the catalyst 1/Zn. Importantly, the involvement of the diethyl phosphoramidate 2 was critical to achieve good enantioselectivities
Non-hydrogen bond catalyst-mediated diastereoselective conjugate additions of 5<i>H</i>-oxazol-4-ones to <i>o</i>-hydroxyphenyl-substituted <i>p</i>-quinone methides
作者:Ziyang Wang、Anqi Huang、Fang Fang、Pengfei Li、Guokai Liu、Wenjun Li
DOI:10.1039/d0ob01558j
日期:——
An efficient DBU-catalyzed conjugateaddition of 5H-oxazol-4-ones to o-hydroxyphenyl-substituted p-quinone methides has been developed, affording the valuable diarylmethanes in high yields with excellent diastereoselectivity. This strategy demonstrates a robust access to a wide range of diarylmethane derivatives possessing biologically significant o-hydroxyphenol and p-hydroxyphenol moieties under
Catalyst-controlled switch of regioselectivity in the asymmetric allylic alkylation of oxazolones with MBHCs
作者:Gongming Zhu、Junxian Yang、Guangjun Bao、Ming Zhang、Jing Li、Yiping Li、Wangsheng Sun、Liang Hong、Rui Wang
DOI:10.1039/c6cc03246j
日期:——
A catalyst-controlled switch of regioselectivity in asymmetric allylicalkylation of oxazolones with MBHCs was described. The proper choice of catalysts could differentiate the SN2'-SN2' and addition-elimination process to yield secondary...
Organocatalytic Enantioselective Michael Addition of Oxazolones to 2‐Enoylpyridine
<i>N</i>
‐Oxides for Assembling of Pyridine
<i>N</i>
‐Oxides Featuring Vicinal Oxygen‐Containing Tetrasubstituted Stereocenters
作者:Yipeng Luan、Anqi Huang、Yuyu Cheng、Xiaohong Liu、Pengfei Li、Wenjun Li
DOI:10.1002/adsc.201900684
日期:2019.9.17
enantioselective Michael addition of 5H‐oxazol‐4‐ones to 2‐enoylpyridine N‐oxides is described. Under mild conditions, a series of optically active pyridine N‐oxides inlaid with oxazolone motif were obtained in high yields (62–99%) with excellent stereoselectivities (84–>99% ee and >20:1 dr). Notably, the method offers a direct synthetic approach to enantioenriched pyridine N‐oxides featured by vicinal
asymmetric Michael reaction between 5H‐oxazol‐4‐ones and α,β‐unsaturated acylimidazoles is reported. A novel 2‐benzo[b]thiophenyl‐modified chiral ProPhenol species is synthesized and used as a ligand, leading to good enantioselectivities in this asymmetric conjugate addition reaction. Furthermore, the introduction of phenol additives as achiral co‐ligands is found to improve the reaction’s chemical yields
据报道,5 H-恶唑-4-酮与α,β-不饱和酰基咪唑之间存在不对称迈克尔反应。合成了一种新型的2-苯并[ b ]硫代苯基修饰的手性脯酚,并用作配体,从而在该不对称共轭加成反应中产生了良好的对映选择性。此外,发现引入苯酚添加剂作为非手性配体可提高反应的化学收率,非对映选择性和对映选择性。