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Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Conformational Control of Chiral Amido-Thiourea Catalysts Enables Improved Activity and Enantioselectivity
Dan Lehnherr1, David D Ford1, Andrew J Bendelsmith1
1Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
Abstract:
While aryl pyrrolidinoamido-thioureas derived from α-amino acids are effective catalysts in a number of asymmetric transformations, they exist as mixtures of slowly interconverting amide rotamers. Herein, the compromising role of amide bond isomerism is analyzed experimentally and computationally. A modified catalyst structure that exists almost exclusively as a single amide rotamer is introduced. This modification is shown to result in improved reactivity and enantioselectivity by minimizing competing reaction pathways.
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