Synthesis of Imidazoles, 2-Pyrrolines and Pyrrolidines via Phospha-Münchnone Cycloadditions
Bibliographic record
Abstract
This thesis describes the use of a new class of dipole, phospha-Mnchnones, in 1,3dipolar cycloaddition reactions.Phospha-Mnchnones can be readily prepared from imines, acid chlorides and the catechyl-substituted phosphonite PhP(2-catechyl).Coupling the multicomponent formation of these dipoles with subsequent cycloaddition has provided modular, one-pot syntheses of a number of heterocycles.In Chapter 1, an overview of the utility of imines in 1,3-dipolar cycloaddition reactions is provided.This includes their use in the synthesis of aromatic nitrogen-containing heterocycles such as of pyrroles, oxadiazoline, imidazoles, triazoles and their reduced analogues.In Chapter 2, research towards the synthesis of imidazoles through the cycloaddition of electron deficient N-nosyl imines with phosha-Mnchnones is described.This transformation allows the direct generation of densely substituted imidazoles in a one-pot fashion, and with high regioselectivity.The methodology is also modular, where the substitution pattern can be altered by simple variation of the building blocks (imine, acid chloride and N-nosyl imine).Alternatively, N-nosyl substituted imines can be replaced by nitriles in intramolecular cycloaddition reactions.This allows the synthesis of polycyclic imidazoles from nitrile-tethered imines and acid chlorides.To the best of our knowledge, this is the first report of intamolecular nitrile dipolar cycloaddition reactions in imidazole synthesis.Chapter 3 focuses on the intramolecular cycloaddition of phospha-Mnchnones with olefins.The resulting polycyclic 2-pyrrolines are prepared in good yields with high diastereoand regio-selectivity from olefin-tethered imines, acid chlorides and phosphonites.Further reactions of these N-heterocycles are also investigated, including the formation of substituted pyrrolidines under reductive conditions.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.002 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".