Adducts of sila-, germa-, and stannaethenes Me<sub>2</sub>E=C(SiMe<sub>3</sub>)<sub>2</sub> (E = Si, Ge, Sn) with anthracene: syntheses, structures, thermolyses
Bibliographic record
Abstract
The [4 + 2] cycloadducts of Me2E=C(SiMe3)2 (E = Si, Ge, Sn) and anthracene are prepared by reaction of an excess of anthracene in benzene with the [2 + 2] cycloadduct of Me2Si=C(SiMe3)2 and Ph2C=NSiMe3 at 130°C, with Me2Ge(OPh)-CLi(SiMe3)2 at 100°C, and with Me2SnBr-CNa(SiMe3)2 at 80°C, respectively. The mentioned adducts act as sources for the ethenes Me2E=C(SiMe3)2 above 100°C, the intermediate formation of which has been demonstrated by trapping experiments with 2,3-dimethylbutadiene (formation of a [4 + 2] and an ene reaction product). The half life time of the anthracene adducts with E = Si, Ge, and Sn in the presence of DMB (= 2,3-dimethylbutadiene) in benzene on thermolysis at 130°C (first order reactions) is found to be 141, 12, and 0.3 h, respectively. In the absence of DMB, thermolysis of the cycloadducts leads in benzene as reaction medium exclusively to the dimers of the Me2E=C(SiMe3)2 intermediates. In toluene as reaction medium ene products of Me2E=C(SiMe3)2 are observed in addition to the dimers. The ene products are not isolable as such, but only after migration of the Me2E-CH(SiMe3)2 substituents. The formed derivatives C6H5CH2EMe2CH(SiMe3)2 of toluene in part give a second ene reaction with another Me2E=C(SiMe3)2 molecule. X-ray structure analyses of the mentioned sources in fact prove the latter to be normal [4 + 2] cycloadducts of Me2E=C(SiMe3)2 and anthracene.Key words: silaethene, germaethene, stannaethene, [4 + 2] anthracene adducts, [4 + 2] cycloadditions and reversions, ene reactions, X-ray structure analyses.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".