Enhanced Reactivity Results in Reduced Catalytic Performance: Unexpected Ligand Reactivity of a Bis(<i>N</i>-2,6-diisopropylphenylperflourophenyl-amidate)titanium-bis(diethylamido) Hydroamination Precatalyst
Bibliographic record
Abstract
A bis(amidate)titanium-bis(amido) complex incorporating electron withdrawing pentafluorophenyl substituents has been prepared to enhance reactivity in this class of hydroamination precatalyst. This bis( N -2,6-diisopropylphenylperflourophenylamidate)titanium-bis(diethylamido) titanium complex has been fully characterized, including its X-ray crystal structure. As a precatalyst, the title compound proved to be effective for intermolecular hydroamination of internal and terminal alkynes with primary amines with yields as high as 97% and modest intramolecular alkene hydroamination. However, the elevated reactivity of this complex also resulted in reduced Markovnikov/anti-Markovnikov selectivity with some terminal alkynes. Substrate scope limitations revealed that this complex is susceptible to decomposition as a direct consequence of nucleophilic addition of the amine substrate to the pentafluorophenyl substituent of the amidate ligand.
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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".