This thesis is divided into four chapters that describe the new development in rhodium-catalyzed addition reactions and asymmetric ring opening (ARO) reactions of strained alkenes.
Chapter 1 describes a regioselective Rh(I)-catalyzed addition reaction of arylboronic acids to unactivated alkenes - protected allylic amines and allyl sulfones. These formal hydroarylation processes have significantly advanced the substrate scope. Comprehensive studies were carried out to optimize the reaction conditions and a wide range of arylboronic acids were employed. The reaction was found to be linear-selective and a mechanism based on functional group- directing effects has been proposed.
Chapter 2 discloses the discovery of Rh(I)-catalyzed addition of arylboronic acids to (benzyl- /arylsulfonyl)acetonitriles. Novel β-sulfonylvinylamine products were formed in a stereoselective fashion (Z-alkene). Upon hydrolysis, β-keto sulfones were obtained with a broad scope of aryl and sulfonyl substituents. These (Z)-β-sulfonylvinylamines were useful synthons in the synthesis of unsymmetrical polysubstituted pyridines via 1-aza-allyl anion intermediates as well as 1,4- benzothiazine derivatives via intramolecular cyclization. Chapter 3 reports the use of two new nucleophiles in Rh(I)-catalyzed ARO of oxabicyclic alkenes - water and triethylamine trihydrofluoride. In the water-induced ARO, an unprecedented domino ARO/isomerization process was discovered which led to the formation of 2-hydroxy-1- tetralones. By modifying the reaction conditions, trans-1,2-diols can be obtained in excellent enantioselectivity. Using triethylamine trihydrofluoride as a nucleophile, an aliphatic C-F bond was constructed enantioselectively in the ring-opening process which provided fluorinated building blocks containing both allylic fluoride and fluorohydrin units.
Finally, Chapter 4 details the development of a one-pot synthesis of a chiral dihydrobenzofuran framework using Rh-catalyzed asymmetric ring opening and Pd-catalyzed C-O coupling. The product can be obtained in excellent enantioselectivity without isolation of intermediates. Systematic metal-ligand studies were carried out to investigate the compatibility of each catalytic system using product enantiopurity as an indicator.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/36019 |
| Date | 13 August 2013 |
| Creators | Tsui, Chit |
| Contributors | Lautens, Mark |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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