Nonplanar Aromatic Compounds. 3. A Proposed New Strategy for the Synthesis of Buckybowls. Synthesis, Structure and Reactions of [7]-, [8]- and [9](2,7)Pyrenophanes
Bibliographic record
Abstract
A new strategy for the synthesis of Buckybowls is presented and initial attempts to implement it are reported. This involves annulation of further rings onto polycyclic aromatic systems that prefer to be planar but have been "pre-bent" by the installation of a tether. Pyrenophane 2b reacts with TCNE and PTAD to give 1:1 and 1:2 adducts, respectively. The less strained pyrenophane 2c is unreactive toward TCNE but gives a 1:2 adduct with PTAD. Attempted electrophilic aromatic brominations of pyrenophane 2e under a variety of conditions were unsuccessful, as were attempts to brominate cyclophanediene 1c, the direct synthetic precursor of 2c. Tether cleavage and addition reactions occurred rather than substitution. In an effort to circumvent tether cleavage problems, [7]-, [8]- and [9](2,7)pyrenophanes 22b-d were prepared. However, attempted bromination and Friedel-Crafts acylations failed. Evidence for the fleeting existence of [6](2,7)pyrenophane 22a was also obtained. Comparison of structural data (X-ray and AM1 calculations) for the pyrenophanes 22a-d with their 1,n-dioxa analogues 2a-d indicates that the nature of the tether has a strong effect on the degree of bend in the pyrene moiety and this led to the identification of trioxapyrenophane 28 as the next target in the quest for increasingly bent pyrenes.
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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 | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".