Allenylketenes: Versatile Substrates in Nucleophilic, Electrophilic, and Cycloaddition Reactions
Bibliographic record
Abstract
All articles of this category 4-Methylene-2-trimethylsilyl-3-phenylcyclobutenones 3 are obtained from the corresponding cyclobutenedione 7 by Tebbe and Peterson methylenation reactions, and upon photolysis give 3-phenyl substituted allenylketenes R 1 CH=C=C(Ph)C(SiMe 3 )=C=O 4 . These are more reactive in ring closure back to 3 than are the 3-trimethylsilyl analogs 1 , as predicted on the basis of molecular orbital calculations. Reactions of allenylketenes 1 and 4 include addition of H 2 O followed by cyclization to form butenolides 13 , addition of aniline to give allenyl carboxamide 14 and lactam 15 , addition of CF 3 CO 2 H to form allenyl carboxylic acid 17 , addition of Br 2 in a 1,4-fashion to give penta-2,4-dienoic acid derivatives 18 , and reaction with m -chloroperbenzoic acid to give the unique allenyl acylsilane 23 . [4 + 1]-Cycloaddition reactions of 1 and 4 with Me 3 SiCHN 2 give methylenecyclopentenones 24 and 25 while acetaldehyde undergoes BF 3 · OEt 2 catalyzed [2 + 2] cycloadditions forming β-lactones. [4 + 2] Cycloadditions occur with benzaldehyde to form the highly crowded exomethylene pentenolactone 29 , and with TCNE forming methylenecyclohexenones 31 . allenes - ketenes - cyclobutenones - cycloaddition - silyl substituents - addition reactions - olefination reactions
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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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".