Resolution of carboxylic acids using copper(I)-promoted removal of propargylic esters under neutral conditions
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Synthesis of Esters Via a Greener Steglich Esterification in Acetonitrile
Published on: October 30, 2018
1Chemical Methodologies and Library Development Center, 2034 Becker Drive, University of Kansas, Lawrence, Kansas 66047-3761, United States.
Abstract:
A method for the optical resolution of carboxylic acids is described. Condensation of racemic carboxylic acids with chiral terminal propargyl alcohols gave separable diastereomeric esters. Chromatographic separation followed by heating the individual diastereomers in methanol with catalytic copper(I) halide regenerated the carboxylic acids in good yields and in enantiomeric ratios of ≥94%. This method is particularly useful for the resolution of carboxylic acids that are incompatible with conventional ester hydrolysis.
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