Mechanism of the lithiumiodine exchange in an iodothiophene
Bibliographic record
Abstract
Solutions of 2-lithio-5-methylthiophene (4) were characterized using DNMR techniques and shown to be a mixture of monomer and dimer in THFEt 2 O (3:2). The hypervalent iodine ate complex 5 (Ar 2 I Li + ), a presumed intermediate in the LiI exchange with 2-iodo-5-methylthiophene, was observed by 13 C and 7 Li NMR spectroscopy at low temperatures (130 °C). At higher temperatures, the ate complex coalesced with 2-lithio-5-methylthiophene. A kinetic scheme was developed, which accounts for the exchange of the monomer 4M, dimer 4D, and 2-iodo-5-methylthiophene (6) with the ate complex 5. The rates of the various exchanges were obtained through a DNMR analysis of the variable temperature 13 C and 7 Li NMR spectra, and the thermodynamic and activation parameters were calculated. The monomer 4M and the ate complex 5 have similar reactivity as aryl donors in the LiI exchange reaction, but 4M is at least 1000 times as reactive as the dimer 4D towards the iodide.Key words: halogenmetal exchange, lithium iodinate, iodine ate complex, lithium reagent, aggregate reactivity.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".