Synthesis and screening of novel ligands for asymmetric catalysis /
Chiral ligands with novel structures have been synthesized and screened for activity in transition metal catalyzed asymmetric transformations. Libraries of ligands were shown to be advantageous because similar structures can be prepared more efficiently via divergent synthesis and because minor str...
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
2001.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=726104741&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Chiral ligands with novel structures have been synthesized and screened for activity in transition metal catalyzed asymmetric transformations. Libraries of ligands were shown to be advantageous because similar structures can be prepared more efficiently via divergent synthesis and because minor structural variations can have a marked impact on catalytic activity. Libraries of C₃-symmetric phosphines have been synthesized and studied using circular dichroism and X-ray crystallography. C₃-phosphine palladium complexes catalyzed asymmetric allylation reactions with some of the highest enantiomeric excesses yet obtained with monodentate phosphine ligands. New imidazol-2-ylidene oxazolines have been synthesized. Iridium complexes of these ligands were shown to be effective catalysts in asymmetric hydrogenation reactions. In one case, a stilbene derivative was hydrogenated resulting in 99 % yield and 98 % ee. These complexes give enantioselectivities comparable to the best hydrogenation catalysts in other asymmetric hydrogenations and are the best asymmetric catalysts of any type containing imidazol-2-ylidene ligands. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xiii, 232 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 74-82). |