Chemistry with chiral lithium amides: enantiotopic group and face-selective reactions

The accomplishment of the γ-alkylation reaction from β-keto esters of tropinone and the enantioselective aziridine formation from nortropinone is first reported. This opened two new paths to develop tropinone enolate chemistry. One is indirect α-alkylation of tropinone, another is the nucleophilic attack from α-C enolate to the nitrogen atom. Seven interesting chiral amines have been synthesized and applied into the enolate chemistry of two interesting precursors of synthesis of natural products: 1,4- cyclohexanedione monoethylene ketal and tropinone.The aldol reaction between the lithium enolate of 1,4-cyclohexanedione monoethylene ketal and benzaldehyde demonstrated the high diastereoselectivity (up to 98% de) and the moderate to high enantioselectivity (up to 75% ee) induced by those chiral lithium amides. On the other hand, high diastereoselectivity (up to 100% de) and the low enantioselectivity were obtained from the aldol reaction of tropinone enolate with benzaldehyde differentiated by chiral lithium amides with extra electron donor atoms. An analysis method to determine enantioselectivity from racemic α-hydroxytropinone was developed. That will, no doubt, benefit the further enantioselective α-hydroxylation reaction of tropinone.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Saskatchewan

Year dc:date.issued

2007

Author dc:creator

• Wang, Li

Advisor dc:contributor.advisor

• Majewski, Marek

• lithium amide
• Enantiotopic group&face selective

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/10388/etd-10312007-165406

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/etd-10312007-165406