PhP=CPh<sub>2</sub> and Related Phosphaalkenes: A Solution Equilibrium between a Phosphaalkene and a 1,2‐Diphosphetane
Bibliographic record
Abstract
The synthesis of phosphaalkenes, ArP=C(R)Ph ( 1 , a : Ar = Ph, R = Ph; b : Ar = o ‐Tol, R = Ph; c : Ar = Mes, R = H), bearing sterically less hindered substituents is reported. Phosphaalkenes 1a – b were prepared by treating Ph 2 C=O with ArP(Li)SiMe 3 , whereas 1c was accessed from the AlCl 3 ‐mediated reaction of ArP(SiMe 3 ) 2 and PhC(O)H. Both 1a and 1b dimerize to afford their respective 1,2‐diphosphetanes ( 2a and 2b ). Compound 2a was characterized by X‐ray crystallography. Dissolution of pure 2a in THF resulted in a temperature dependent equilibrium with monomer 1a (Δ H o = –94.6 ± 14.6 kJ mol –1 ; Δ S o = –284 ± 48 J mol –1 K –1 ). Although monomer E/Z ‐ 1c was identified in solution by its characteristic downfield 31 P NMR chemical shift ( δ = 247.1, 231.5), it was accompanied by the formation of what we believe are oligomers ( δ = –25 to 10 ppm, br.). Attempts to trap phosphaalkenes 1a and 1b by treatment with W(CO) 5 (MeCN) afforded mixtures of complexes W(CO) 5 ( 1a – b ) ( 4a – b ) and W(CO) 4 ( 1a – b ) 2 ( 5a – b ), the disubstituted species being subjected to X‐ray crystallographic characterization ( 5a ).
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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 | 0.001 | 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 | 0.000 | 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 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".