Stereoselective synthesis of cyclopentanoids and cyclitol derivatives originated from polychlorinated norbornene systems


Thesis Type: Doctorate

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

Approval Date: 2009

Thesis Language: English

Student: Ayşegül Gümüş

Supervisor: CİHANGİR TANYELİ

Abstract:

Optically active polychlorinated norbornene systems are important starting compounds for the synthesis of many complex molecules. The synthetic strategy of this study mainly depends upon the enzymatic resolution of hydroxymethyl-substituted polychlorinated norbornene structures. The enantiomerically enriched acetoxymethyl derivatives were synthesized in high ee values by several lipases. The absolute configuration of tetrachlorinated norbornene system was determined by X-ray analysis. The second part of the thesis involves the ruthenium and cerium-catalyzed oxidation reactions of various polychlorinated norbornene derivatives to afford α-diketones. The regioselectivity of ruthenium catalyst was tested in polychlorinated norbornadiene systems. In the third part of the study, cyclopentanoid derivatives were synthesized in high chemical yield starting from enantio-enriched both tetra- and hexa-chlorinated norbornene derivatives. In the last part of the study, stereo- and regioselective synthesis of carbasugar systems which are potential glycosidase inhibitors were performed. Starting from enantio-enriched acetoxymethyl substituted tetrachloro norbornene system both carbasugar by cleavage of C1-C7 bond and ‘confused’ carbasugar by cleavage of C4-C7 bond were synthesized.