Selective Catalytic Dimerization of Neohexene by [Cp*Ti(NP<sup>t</sup>Bu<sub>3</sub>)Me][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]
Bibliographic record
Abstract
The known titanium alkyl cation [Cp*Ti(NP t Bu 3 )Me][B(C 6 F 5 ) 4 ], supported by a bulky phosphinimide donor, was found to react with 3 equiv of 3,3-dimethyl-1-butene (neohexene) to generate another alkyl cation in which the alkyl group is derived from two dimerized equivalents of the substrate olefin. This species, 1, was characterized in detail by spectroscopic methods and via X-ray crystallographic determinations of two of its derivatives, the THF adduct ( 2 ) and the neutral chloride derivative 3 formed upon addition of Cl − to 1 . Detailed mechanistic experiments suggest 1 is formed via insertion of neohexene into the Ti−Me bond of [Cp*Ti(NP t Bu 3 )Me][B(C 6 F 5 ) 4 ] to give a detectable intermediate ( 4 ), which was characterized spectroscopically. Cation 4 reacts in a σ-bond metathesis reaction with the olefinic C−H bond trans to the tert -butyl group of another equivalent of neohexene to form an undetected cationic vinyl intermediate, which rapidly inserts a third equivalent of neohexene to generate 1 . Deuterium labeling studies are consistent with this mechanistic picture. Compound 1 is the resting state of a catalytic cycle for dimerization of neohexene; under catalytic conditions (95 °C, [neohexene] = 1.1 M, 1.2−2.1 mol% 1 ), clean conversion of neohexene to ( E )-2,2,5,6,6-pentamethylhept-3-ene was observed, with total turnovers of 44—78.
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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 | 0.000 |
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 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".