Synthesis and Reactivity of Functionalized Fluoro-Nickelacyclopentanes
Bibliographic record
Abstract
Fluoro-nickelacyclopentanes are key intermediates in the synthesis of hydrofluoro-carbons and fluorinated ketones. To better understand substituent effects on their reactivity, we have prepared a series of nickel complexes from perfluoro(methyl vinyl ether) (PMVE) and chloro-trifluoroethylene (CTFE). Both fluoroalkenes react with Ni(cod) 2 + 2 equiv of P(O i Pr) 3 to give regioselective formation of the tail-to-tail nickelacyclopentanes Ni[–CFX(CF 2 ) 2 CFX–][P(O i Pr) 3 ] 2 (X = OCF 3, Cl) as a 3:1 mixture of the trans / cis diastereomers for PMVE and the trans diastereomer selectively for CTFE. Reaction of both metallacycles with 1,2-bis(diphenylphosphino)ethane (dppe) displaces the phosphite ligands, affording two (X = OCF 3 ) or one (X = Cl) diastereomer of electron-rich congeners Ni[–CFX(CF 2 ) 2 CFX–](dppe). Although these dppe-derived metallacycles did not react cleanly with fluoride-abstracting Lewis acids (Et 2 O·BF 3 or Me 3 SiOTf), heating trans -Ni[–CFCl(CF 2 ) 2 CFCl–](dppe) induced the intramolecular nucleophilic attack by one –PPh 2 arm of the dppe ligand on a C–Cl bond, affording both trans and cis diastereomers in a 1:1 ratio. Using the wider bite-angle bis(phosphine) xantphos with PMVE also gave the trans / cis nickelacyclopentanes, which feature κ 3 - P,O,P -xantphos coordination. With CTFE, the xantphos ligand gave an unexpected fluoro-nickelacyclopentane derivative proposed to result from tail-to-tail oxidative cyclization, followed by PPh 2 + migration, leading to an unusual coupling of the fluoroalkyl moiety with the xanthene backbone.
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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) | 0.003 | 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".