[5+2] Cycloadditions to Form Oxobicyclo[3.2.1]octanes Public
Bolton, Emily Nora (2010)
Abstract
Organometallic scaffolds have been studied for alternative strategic and structural approaches to enantiomeric bond construction. These scaffolds may be used to synthesize a variety of natural products such as Bao Gong Teng A. Over the past 20 years the Liebeskind lab has focused on one such scaffold, TpMo(CO)2(η3-oxopyranyl) (Tp=hydridotrispyrazolylborato). In this thesis, an analogous tungsten complex, TpW(CO)2(η3-oxopyranyl), has been explored for the purpose of scientific curiosity. The η3-oxopyranyltungsten scaffold was synthesized in three steps: Achmatowicz oxidative rearrangement of furfuryl alcohol, acetylation of the intermediate , and finally oxidative addition of the substrate to the metal. The reactivity of the resulting η3-oxopyranyltungsten scaffold was studied through Lewis acid mediated [5+2] cycloadditions. It was observed that the synthesis of the TpW(CO)2(η3-oxopyranyl) scaffold was higher yielding than its molybdenum counter-part, TpMo(CO)2(η3-oxopyranyl) scaffold. Additionally, an unusual Friedel-Crafts product was formed after Grignard reagent addition and in a few of the [5+2] cycloaddition examples.
Table of Contents
Introduction
Tungsten zero-valent sources
Preparation of the η 3-5-oxo-pyranyl tungsten scaffold
Synthesis of η 3-5-hydroxy-5-methyl (or phenyl)pyranyl tungsten compound
Synthesis of the fully unsaturated tungsten scaffold
Synthesis of a variety of [5+2] cycloadducts
Synthesis of the enantiomeric TpW(CO)2( η 3-oxopyranyl) Scaffold
Spectral property differences between molybdenum and tungsten scaffolds
Conclusion ExperimentalMethods and materials
Tungsten metallation sources
Synthesis of the racemic tungsten oxopyranyl scaffold
Synthesis of the enantiomerically pure tungsten oxopyranyl scaffold
Synthesis of (±)-Dicarbonyl[hydriotris(1-pyrazolyl)borato][ η -(2,3,4)-5-methyl-5-hydroxy-2H-pyran-2-yl]tungsten
Synthesis of (±)-Dicarbonyl[hydriotris(1-pyrazolyl)borato][ η -(2,3,4)-5-phenyl-5-hydroxy-2H-pyran-2-yl]tungsten
Synthesis of Dicarbonyl[hydridotris(1-pyrazolyl)borato][ η -(2,3,4)-5-methyl-2H-pyran-2-yl]tungsten
Synthesis of Dicarbonyl[hydridotris(1-pyrazolyl)borato][ η -(2,3,4)-5-phenyl-2H-pyran-2-yl]tungsten
Synthesis of [5+2] Cycloaddition Products
ReferencesAbout this Master's Thesis
School | |
---|---|
Department | |
Degree | |
Submission | |
Language |
|
Research Field | |
Mot-clé | |
Committee Chair / Thesis Advisor | |
Committee Members |
Primary PDF
Thumbnail | Title | Date Uploaded | Actions |
---|---|---|---|
[5+2] Cycloadditions to Form Oxobicyclo[3.2.1]octanes () | 2018-08-28 14:17:43 -0400 |
|
Supplemental Files
Thumbnail | Title | Date Uploaded | Actions |
---|