ORGN 447 |
Short, efficient route to enantiopure biprolines
| Ashish P Vartak and Rodney L. Johnson. Department of Medicinal Chemistry, University of Minnesota, 8-101 Weaver Densford Hall, 308 Harvard St. SE, Minneapolis, MN 55455 |
| In our attempts at an expedient route to type VI beta-turn mimics, we discovered a 3-step alkylation-elimination-alkylation pathway by which two molecules of the lithium enolate of Seebach’s oxazolidinone (1) dimerize to give the biprolyl oxazolidinones 2 and 3 when treated with electrophiles of type XC-CX. We found the stereochemical outcome to be dependent on temperature and solvent polarity; reaction in THF-hexanes at low temperatures favoring 2, while higher temperatures and addition of HMPA favored 3. The biprolyl oxazolidinones could be hydrolyzed cleanly to the unique (R,R) biproline (4) and meso-biproline (5) respectively. 
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Total Synthesis, Process R&D, Combinatorial, Bioorganic, Physical Organic Chemistry
8:00 PM-10:00 PM, Tuesday, August 24, 2004 Pennsylvania Convention Center -- Hall D, Poster
Sci-Mix
8:00 PM-10:00 PM, Monday, August 23, 2004 Pennsylvania Convention Center -- Hall D, Sci-Mix
Division of Organic Chemistry
The 228th ACS National Meeting, in Philadelphia, PA, August 22-26, 2004
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