SnCl<sub>4</sub>I<sub>2</sub> mediated regioselective 6-endo- and 5-exo-cyclization of <i>ortho</i>-allylenols
Bibliographic record
Abstract
3-Allyl-4-hydroxycoumarins and 4-allyl-3-hydroxycoumarins are obtained in 90%92% yields by the thermal [3,3] sigmatropic rearrangement of the corresponding ethers. 3-Allyl-4-hydroxy-6-methylpyrone is obtained from the direct alkylation of 4-hydroxy-6-methylpyrone with allyl halide. These substrates on treatment with SnCl 4 I 2 at 25 °C give a mixture of both 5-exo- and 6-endo-cyclization products. However, regioselective formation of 5-exo products is observed when the reactions are conducted at lower temperatures (05 °C, kinetically controlled), while the reaction at a higher temperature (50 °C, thermodynamically controlled) affords regioselectively 6-endo cyclization products.Key words: stannic chloride, iodine, claisen rearrangement, 6-endocyclization, 5-exocyclization, kinetically controlled reaction, thermodynamically controlled reaction.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".