Synthesis and enzymatic resolution of various cyclopentenoid and cyclohexenoid type compounds


Thesis Type: Doctorate

Institution Of The Thesis: Middle East Technical University, Faculty of Arts and Sciences, Department of Chemistry, Turkey

Approval Date: 2005

Thesis Language: English

Student: Çiğdem İyigün

Supervisor: CİHANGİR TANYELİ

Abstract:

The aim of this thesis is to synthesize enantiomerically enriched cyclopentenoid and cyclohexenoid type of compounds with quaternary carbon stereocenters that are the simplest precursors of the complex natural products. The first part of the study involves the preparation of ?'-acetoxy ?'-substituted ?,β-unsaturated cyclic ketones. Methylation, ethylation, benzylation and allylation of cyclohexenone and cyclopentenone derivatives are performed. Then, these compounds are regioselectively oxidized at the ?'-position by Mn(OAc)3. This is the first successful example in the literature that ?'-tert-position is oxidized by Mn(OAc)3. The oxidations were also performed by Pb(OAc)4 and both methods were compared. Related to this study, in the second part, the enantiomeric resolution of the acetoxy derivatives were performed by various hydrolases. This study is the first example where the hydrolases are used to resolve tertiary positions. Among the enzymes used, Candida cylindracea lipase (CCL) showed the best enantioselectivity.