Diastereoselective formation of 18-membered ring BINOL-hydrogen phosphonate dimers - Quasi-covalent hydrogen bonds?
Why this work is in the frame
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Bibliographic record
Abstract
Diastereoselective syntheses of the unusual dimers, 4-heptyl-2-(2′-hydroxy-binaphthyl)hydrogen phosphonate (5) and the cyclohexyl analogue (7), are achieved by hydrolysis of 4-(3,5-dioxa-4-phosphacyclohepta[2,1-α;3,4-α′]-dinaphthalene-4-yloxy)heptane (4) and the cyclohexane analogue (6), respectively. Two out of eight possible pairs of monomers units are involved in the stereoselective formation of the dimer 5a of configuration BINOL R -P S :BINOL R -P S ; this is determined by X-ray crystallographic data, which reveal a centrosymmetric, 18-membered ring structure with C i symmetry, consisting of two monomers strongly hydrogen-bonded between the oxygen of P=O units and hydroxyl hydrogen atoms. Mass spectrometric, melting point, and thermal decomposition point data, as well as NMR data, support the presence of strong, quasi-covalent hydrogen bonds. Computational analysis suggests that the diastereoselectivity is controlled by molecularly constrained geometry of the monomer. Compound 7, although not characterized crystallographically, appears to be analogous to 5.Key words: 18-membered ring, phosphonate dimer, diastereoselectivity, hydrogen-bonds, computational analysis.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 it