190378-46-2Relevant academic research and scientific papers
FLUOROUS OXAZOLIDINONE CHIRAL AUXILIARY COMPOUNDS AND METHODS OF MANUFACTURE
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Page/Page column 8-9, (2008/06/13)
The present invention relates generally to perfluoroalkyl chiral auxiliary compounds and methods of manufacture. These compounds have the functionality to effectively support the synthesis of chiral compounds in single reactions, high-throughput parallel recations, or combinatorial reactions The invention relates to two oxazolidmone chiral auxiliaries (1) and (2): wherein Rf is a perfluoroalkyl group having the general formula (CH2)x-CyF2y+1 where x = 1-5 and y = 4-10 and wherein B is an unfunctionalized aryl, alkyl or arylalkyl group Pn a preferred embodiment, x = 2 and y = 6 and B is derived from unfunctionalized ammo acids The ammo acids may be from either the D- or L- series, and are preferably enantiomeπcally pure or in very high enantiomeric excess in either configuration.
Stereoselective conjugate radical additions: Application of a fluorous oxazolidinone chiral auxiliary for efficient tin removal
Hein, Jason E.,Zimmerman, Jake,Sibi, Mukund P.,Hultin, Philip G.
, p. 2755 - 2758 (2007/10/03)
(Chemical Equation Presented) A series of asymmetric free-radical-mediated intermolecular conjugate additions using a fluorous oxazolidinone chiral auxiliary has been completed. The fluorous auxiliary facilitated product isolation using fluorous solid phase extractions (FSPE), effectively removing excess organic and organometallic reagents. Parallel reactions carried out with a similar but nonfluorous norephedrine-derived oxazolidinone demonstrated the superior stereoselectivity and purification obtainable with the fluorous chiral auxiliary.
Practical synthesis of fluorous oxazolidinone chiral auxiliaries from α-amino acids
Hein, Jason E.,Geary, Laina M.,Jaworski, Ashley A.,Hultin, Philip G.
, p. 9940 - 9946 (2007/10/03)
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.
