1008530-33-3Relevant academic research and scientific papers
Synthesis of amine functionalized oxazolines with applications in asymmetric catalysis
Miller, Jeremie J.,Rajaram, Sridhar,Pfaffenroth, Cornelia,Sigman, Matthew S.
scheme or table, p. 3110 - 3119 (2009/09/05)
This paper describes the synthesis of three classes of amine functionalized oxazolines that have been successfully used in asymmetric catalysis in our laboratory. Failed synthetic routes and significantly improved procedures are discussed including the synthesis of ligands for Nozaki-Hiyama-Kishi (NHK) carbonyl allylation reactions that do not require chromatography for purification.
Examination of the role of Taft-type steric parameters in asymmetric catalysis
Sigman, Matthew S.,Miller, Jeremie J.
supporting information; experimental part, p. 7633 - 7643 (2009/12/27)
(Chemical Equation Presented) We report the use of Taft steric parameters to correlate the substituent size of a ligand with the enantiomeric ratio of a reaction. Linear free energy relationships can be constructed by plotting the log of enantiomeric ratio (er) versus the steric parameters reported by Taft and modified by Charton. Successful correlations were found for aldehyde and ketone allylation under NHK conditions using modular oxazoline ligands developed in our laboratory. Using these correlations, ligands were designed and evaluated for carbonyl allylation reactions. A break in the Charton plot results and is attributed to a global structural change in the catalyst. Additionally, several previously reported enantioselective reactions are analyzed resulting in excellent correlations for both catalysts and substrates. Finally, limitations and issues are presented with illustrative examples.
Quantitatively correlating the effect of ligand-substituent size in asymmetric catalysis using linear free energy relationships
Miller, Jeremie J.,Sigman, Matthew S.
, p. 771 - 774 (2008/12/20)
Is bigger better? By systematically evaluating the size of the substituent G in a modular ligand (see picture), a linear free energy relationship was observed relating the product enantiomeric ratio to steric parameters developed by Charton. The reaction
