Synthesis and Structure of Spirocyclic Tetraethers Derived from [1,1′-Binaphthalene]-2,2′-diol and Pentaerythritol
Bibliographic record
Abstract
Molecular scaffolds that have well-defined geometries, are easy to synthesize and functionalize, and can hold attached sites of molecular recognition in suitable orientations are useful tools in various areas of science and technology. The utility of the tetraphenyl ether of pentaerythritol (4) as a scaffold in crystal engineering led us to study rigidified analogue SBINOX (5), the spirocyclic tetraether derived from pentaerythritol and [1,1'-binaphthalene]-2,2'-diol (BINOL). We have found that SBINOX (5) and derivatives can be prepared conveniently in acceptable yields and in stereoisomerically pure (S,S), (R,S), and (R,R) forms. X-ray crystallographic studies have revealed that the benzannulated 9-membered dioxonane rings in these structures adopt characteristic conformations of C1 symmetry. Intraannular C-H...O interactions help maintain the conformations of the individual rings, and the geometry of the spirocyclic SBINOX core is also controlled in part by distinctive short interannular C-H...O and C-H...pi interactions. Despite the inherent flexibility of the dioxonane rings, derivatives of SBINOX (5) can be expected to orient peripheral substituents in preferred ways, making SBINOX a potentially useful scaffold for applications in drug discovery, crystal engineering, and other fields.
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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) | 0.001 | 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".