Synthesis, Conformational Properties and DFT Computational Studies of Polymethyl‐Substituted [3.3]Metacyclophanes
Bibliographic record
Abstract
Abstract Polymethyl substituted [3.3]metacyclophanes (MCPs) 4 a–d , were synthesized by the TosMIC coupling method followed by Wolff–Kishner reduction of the corresponding polymethyl‐substituted [3.3]MCP‐2,11‐diones ( 3 a–d ). 1 H NMR spectroscopy reveals that both 5,6,7,14,16‐pentamethyl[3.3]MCP‐2,11‐diones ( 3 a and 3 b ) undergo conformational changes relative to the NMR time scale in solution at room temperature but that the anti conformer is preferred. Reduced 5,6,7,14,16‐pentamethyl[3.3]MCP ( 4 a and 4 b ) adopt fixed syn– conformations in solution at room temperature. X‐ray analysis showed that in the solid state, 5,6,7,14,15,16‐hexamethyl[3.3]MCP‐2,11‐dione 3 a adopts the anti ‐conformation and reduced 5,6,7,14,16‐pentamethyl[3.3]MCP‐2,11‐diones 4 b adopts a syn‐ (chair‐chair) conformation. A series of electrophilic substitution reactions such as formylation, acetylation and nitration were carried out with 5,6,7,14,16‐pentamethyl[3.3]MCP 4 b to study their conformational isomers. The formyl, acetyl and nitro derivatives of 5,6,7,14,16‐pentamethyl[3.3]MCP are fixed to adopt syn ‐conformations in solution at room temperature. The conformational isomers of the metacyclophanes and derivatives obtained from density functional theory (DFT) methods were used to estimate the total energies and energy minimized structures of the different conformations.
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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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".