Synthetic and mechanistic investigations of a diruthenium-catalyzed C-H amination reaction
Abstract/Contents
- Abstract
- The development of efficient and selective rhodium-catalyzed C--H and [pi]-bond amination processes makes possible unprecedented C--N bond disconnections in the synthesis of complex molecules. The oxidizing conditions of the reaction, however, have limited a broad utilization of catalyst structures beyond the well-documented bimetallic tetracarboxylates. Our desire to uncover catalyst systems tolerant of a wider range of ligand architectures inspired an evaluation of a congeneric class of diruthenium complexes that feature higher oxidation potentials. These studies have culminated in the identification of a family of efficacious amination catalysts crafted from a diruthenium core. Empirical examinations have demonstrated exceptional performance for the strapped carboxylate catalyst [Ru2(esp)2]SbF6 in amination reactions, and a unique proclivity for allylic C--H bond oxidation exacted by the tetrakis-oxypyridinate complex [Ru2(hp)4Cl]. Density functional calculations on this latter catalyst have implicated a mechanism for C--H insertion that operates via an H-atom abstraction/radical rebound sequence, contrasting the body of work on intramolecular amination by dirhodium systems. Experimental studies were undertaken to corroborate the stepwise nature of the catalytic reaction and to dissect the details of the insertion event. Investigations of alternative pathways operating in parallel to productive turnover have unveiled a host of processes that effect substrate or product consumption, oxidant depletion, and global catalyst reorganization. With the assistance of desorption electrospray ionization mass spectrometry (DESI-MS), a wealth of mechanistic data has been amassed, including evidence of critical, short-lived reaction intermediates. The collective data provide a detailed mechanistic framework for diruthenium-mediated amination reactions that should assist the continued development of effective and varied C--H amination technologies.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Copyright date | 2014 |
| Publication date | 2013, c2014; 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Harvey, Mark Edwin |
|---|---|
| Associated with | Stanford University, Department of Chemistry. |
| Primary advisor | Du Bois, Justin |
| Thesis advisor | Du Bois, Justin |
| Thesis advisor | Stack, T. (T. Daniel P.), 1959- |
| Thesis advisor | Wender, Paul A |
| Advisor | Stack, T. (T. Daniel P.), 1959- |
| Advisor | Wender, Paul A |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Mark Edwin Harvey. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2014. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2014 by Mark Harvey
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