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Friday 12 December 2014

Direct Catalytic Enantio- and Diastereoselective Mannich Reaction of Isocyanoacetates and Ketimines




Abstract

A catalytic asymmetric synthesis of imidazolines with a fully substituted β-carbon atom by a Mannich-type addition/cyclization reaction of isocyanoacetate pronucleophiles and N-diphenylphosphinoyl ketimines has been developed. When a combination of a cinchona-derived aminophosphine precatalyst and silver oxide was employed as a binary catalyst system, good reactivity, high diastereoselectivities (up to 99:1 d.r.), and excellent enantioselectivities (up to 99 % ee) were obtained for a range of substrates.





Direct Catalytic Enantio- and Diastereoselective Mannich Reaction of Isocyanoacetates and Ketimines

  1. Dr. Irene Ortín and
  2. Prof. Dr. Darren J. Dixon*
Article first published online: 24 FEB 2014
DOI: 10.1002/anie.201309719

Angewandte Chemie International Edition

Volume 53Issue 13pages 3462–3465March 24, 2014


Ortín, I. and Dixon, D. J. (2014), Direct Catalytic Enantio- and Diastereoselective Mannich Reaction of Isocyanoacetates and Ketimines. Angew. Chem. Int. Ed., 53: 3462–3465. doi: 10.1002/anie.201309719

Author Information

  1. Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (UK)
*Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (UK)===

Professor Darren J. Dixon


Department of Chemsitry


















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Saturday 29 November 2014

A route to convert CO2: synthesis of 3,4,5-trisubstituted oxazolones



Green Chem., 2015, Advance Article
DOI: 10.1039/C4GC02033B, Paper
Jiayin Hu, Jun Ma, Zhaofu Zhang, Qinggong Zhu, Huacong Zhou, Wenjing Lu, Buxing Han
CO2 can react with various propargylic amines to form 3,4,5-trisubstituted oxazolones catalyzed by the active, selective and stable ionic liquids.


Production of value-added chemicals using carbon dioxide (CO2) as a feedstock is favorable to the sustainable development of the chemical industry. In this work, we have discovered for the first time that CO2 can react with propargylic amines to produce 3,4,5-trisubstituted oxazolones, a class of very useful chemicals. It was found that the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) can catalyze the reactions efficiently at atmospheric pressure under metal-free conditions. It was also found that [Bmim][OAc] and IL 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([Bmim][Tf2N]) have an excellent synergistic effect for promoting the reactions. The [Bmim][OAc]/[Bmim][Tf2N] catalytic system can be reused at least five times without loss in catalytic activity and selectivity. The reaction mechanism was proposed on the basis of density functional theory (DFT) calculation and the experimental results.