Combinatorial Strategies Applied to Catalyst Development
Final rept. 1 Jun 94-31 May 97
CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY
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The performed research demonstrates that important ligand classes can be synthesized on solid supports and can be used directly without purification to prepare asymmetric catalysts. For the catalyst system that was evaluated, the ligands prepared in parallel on support provided comparable enantioselectivities to purified ligands prepared individually over several steps in solution. Enantioselectivities greater than 90 ee were observed. These results hold promise for parallel synthesis and evaluation approaches in asymmetric catalyst optimization. A sulfinamide chiral auxiliary has also been developed. Auxiliary loading, diastereoselective transformations, and auxiliary removal all proceed in high yields. Auxiliary removal is accomplished by first activating the auxiliary linkage followed by nucleophilic release. Modification of the sulfinamide auxiliary as a support-bound linkage will allow the stereodefined synthesis of libraries of chiral compounds.
- Organic Chemistry