Transition metal-catalyzed bond formations: an expansion of the utility of organotrifluoroborate salts and organoboronic acids
Bibliographic record
Abstract
This thesis is a summary of the research conducted since September 1999 at the University of Toronto in the laboratory of Dr. Robert A. Batey. This manuscript is divided into four chapters. Chapter one provides a general introduction to the nature and reactivity of organo trifluoroborate salts. Their preparation from organoboron or organohalide precursors, as well as their use in a variety of synthetic transformations is reviewed. The preparation of novel tetra- n-butylammonium organotrifluoroborate salts within our own laboratory is also described. Chapter two provides an overview of the classical copper-mediated Ullmann Reaction for carbon-carbon bond formation between aryl halides, as well as modern variations of the Ullmann-Goldberg Condensation for carbon-oxygen bond formation. Our contributions to this area of synthetic chemistry are described, including the copper-catalyzed cross-coupling of potassium aryl- and alkenyltrifluoroborates with unactivated alcohols and phenols, which were achieved in good to excellent yields by utilizing copper acetate monohydrate as catalyst under an atmosphere of oxygen in the presence of 4A molecular sieves. Recent work into the copper-mediated/catalyzed cross-coupling of potassium organotrifluoroborate salts with activated carboxylate salts is also described. Chapter four describes our efforts in the investigation of the mechanism of the cross-coupling. The various stages of the catalytic cycle are examined with particular focus upon the oxidation state of the copper species involved. The role of molecular sieves in the transformation is also explored, as experimental observations have suggested that they play a greater part than just as desiccant in the reaction. Finally, the result of a short study on the phenomenon of the deactivation of the catalytic transformation by the presence of quaternary ammonium species is also presented. Chapter three describes modern approaches to carbon-nitrogen bond formation through the Ullmann-Goldberg Condensation of organometalloid species with nitrogen-based nucleophiles. The result of an investigation into the stoichiometric copper-mediated cross-coupling of potassium organotrifluoroborate salts and anilines is presented. In addition a novel reaction protocol for the ligandless and base free copper-catalyzed arylation of aliphatic amines is presented. The cross-coupling was found to work equally well with both potassium organotrifluoroborate salts and organoboronic acids.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".