American Chemical Society
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Practical Synthesis of Fluorous Oxazolidinone Chiral Auxiliaries from α-Amino Acids

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journal contribution
posted on 2005-11-25, 00:00 authored by Jason E. Hein, Laina M. Geary, Ashley A. Jaworski, Philip G. Hultin
A series of new fluorous-supported oxazolidinone chiral auxiliaries has been prepared using a versatile and general five-step pathway, starting from readily available chiral α-amino acids. The key feature of this synthesis is the efficient generation of a suitably active perfluoroalkyllithium species. By use of this protocol, the auxiliaries can be obtained in high enantiomeric purity and on multigram scales from l-phenylalanine and l-valine with overall yields as high as 55%. The new methodology also incorporates fluorous solid-phase extraction on the large scale, allowing bulk quantities (up to 25 g) of fluorous compounds to be purified from the crude reaction mixture.