Asymmetric allylic oxidation reaction and synthetic studies of glycosaminoglycans
Abstract
In Part I: Asymmetric allylic oxidation of cyclic olefins using a catalytic amount of copper(I) bisoxazoline complexes and new peresters was investigated to give allylic benzoate esters in high selectivity (∼80%ee), yield (70–80%), and at reasonable rates (5–7 d) at −20°C in acetonitrile. Cyclohexene reacted with para-chloro tert -butylperbenzoate and 15 mol% diphenylbisoxazoline-copper(I) hexafluorophosphate to give benzoate product in 83% yield and 75%ee. In Part II: A novel synthetic approach for the glycosidic coupling of uronic acids to hexosamines to achieve modular synthesis of glycosaminoglycans, the biologically important carbohydrates, had been investigated. Results found that silver triflate could disassociated the anomeric linkage of disaccharide thioester at ambient temperature. Attempt to develop an efficient method to synthesize several 13C-labeled uronic acids, such as D-glucuronic acid (GlcA), L-iduronic acid (IdoA) and D-galacturonic acid. The key intermediate, 4-keto derivatives of xylose, were synthesized, and their activities and possibilities of direct carboxylation were investigated.
Degree
Ph.D.
Advisors
Rothwell, Purdue University.
Subject Area
Organic chemistry
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.