Investigations Directed at Catalytic Carbon−Carbon and Carbon−Oxygen Bond Formation via C−H Bond Activation
Bibliographic record
Abstract
A potential catalytic cycle for the formation of new C−C and C−O linkages from hydrocarbon feedstocks and readily available olefin and ketone substrates mediated by Cp‘M(NO)(L) (M = Mo, W; Cp‘ = Cp*, Cp; L = Lewis base) fragments has been investigated. The cycle is based on three steps: (1) oxidative addition of the hydrocarbon substrate to the metal center, (2) subsequent hydrometalation of the olefin or the ketone, and (3) final reductive elimination of the coupled product. Of the various Cp‘M(NO)(L) groups examined, the Cp*W(NO)(PPh 3 ) fragment has been found to be the best candidate for mediating these catalytic steps since it is not prone to form unreactive Cp*W(NO)(PPh 3 ) 2 as are some of the other fragments that readily decompose to 18 e Cp‘M(NO)L 2 complexes. Hence, Cp*W(NO)(PPh 3 ) has been utilized to determine if the oxidative addition and hydrometalation steps can occur sequentially under one-pot experimental conditions. However, olefins are too π-acidic and readily form stable 18 e Cp*W(NO)(PPh 3 )(η 2 -olefin) adducts, which prevent oxidative addition of the hydrocarbon substrate to the tungsten center. Similarly, benzophenone, Ph 2 CO, and diisopropyl ketone, i Pr 2 CO, also form 1:1 η 2 -C O adducts with the π-basic tungsten center in the 16 e fragment. Nevertheless, oxidative addition and hydrometalation do occur sequentially to form the desired aryl alkoxide complex, Cp*W(NO)(OCH i Pr 2 )(Ph), in addition to the Cp*W(NO)(η 2 -OC i Pr 2 )(PPh 3 ) adduct, when benzene and diisopropyl ketone are employed as the two substrates. The solid-state molecular structures of cis -Cp*W(NO)[η 2 -(CH 2 NMe)P(NMe 2 ) 2 ](H), Cp*W(NO)(OCH i Pr 2 )(Ph), and Cp*W(NO)(η 2 -OC i Pr 2 )(PPh 3 ) have been established by single-crystal X-ray crystallographic analyses.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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".