Asymmetrichydrogenation of 4-substituted cyclic enamido esters catalyzed by a rhodium–TangPhos complex provides an efficient method for the synthesis of chiral 4-substituted oxazolinones with excellent yields and good enantioselectivities. The products are valuable chiral building blocks and the applications as chiral auxiliaries and pharmaceuticals are well-known.
B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-catalyzed metal-free hydrogenation of 2-oxazolones
作者:Guangyu Cui、Xiangqing Feng、Haifeng Du
DOI:10.1039/d2ob01950g
日期:——
A metal-free hydrogenation of 2-oxazolones was successfully realized by using 10 mol% of B(C6F5)3 as the catalyst, giving a variety of 2-oxazolidinones in 70–98% yields. An enamine to imine process was believed to be involved in this reaction.
以10 mol%的B(C 6 F 5 ) 3为催化剂,成功实现了2-恶唑酮的无金属加氢反应,得到多种2-恶唑烷酮,收率为70-98%。烯胺到亚胺的过程被认为参与了该反应。
Synthesis of Chiral 2‐Oxazolidinones by Ruthenium‐Catalyzed Asymmetric Transfer Hydrogenation of 2‐Oxazolones
An asymmetric transfer hydrogenation of 2-oxazolones in the presence of a chiral diamine ruthenium catalyst with potassium formate as a hydrogen source and potassium carbonate as an additive in 2,2,2-trifluoroethanol is described. A series of chiral 2-oxazolidinones were obtained with 29%–95% yields and 86%–>99% ee's. Furthermore, gram-scale synthesis of chiral 2-oxazolidinone and its downstream derivatizations
Spiro[indene-1,4′-oxa-zolidinones] Synthesis via Rh(III)-Catalyzed Coupling of 4-Phenyl-1,3-oxazol-2(3<i>H</i>)-ones with Alkynes: A Redox-Neutral Approach
作者:Zhongsu Liu、Wenjing Zhang、Shan Guo、Jin Zhu
DOI:10.1021/acs.joc.9b01804
日期:2019.9.20
C-H activation synthesis of heterocyclic spiro[4,4]nonanes has persistently witnessed the use of additional stoichiometric transition-metal oxidant when employing C═C bond as the spiro ring closure site. Herein, we have addressed the issue by reporting a redox-neutral strategy for spiro[indene-1,4'-oxa-zolidinones] synthesis via Rh(III)-catalyzed coupling of 4-phenyl-1,3-oxazol-2(3H)-ones with alkynes