Intercepting Ketone α-Arylation Intermediates in the DalPhos/Ni-Catalyzed Synthesis of Decorated Benzofurans and NH-Indoles
Bibliographic record
Abstract
Employing meso -PAd2-DalPhos ( meso -L1 ) as an ancillary ligand, a single mechanistic landscape provides access to two thermal nickel-catalyzed transformations with broad scope commencing from α-( o -chloro)aryl ketones: the synthesis of 2-substituted benzofurans via intramolecular O -arylation and the synthesis of 3-acyl-2-substituted NH-indoles when incorporating RCN reactants. Through the isolation of intermediates and kinetic analysis, the synthesis of 3-acyl-2-substituted NH-indoles is proposed to occur through a Ni(0/II) catalytic cycle involving: (1) ( meso -L1 )Ni(0) oxidative addition of the aryl chloride; (2) base-facilitated HCl loss forming a Ni(II) κ 2 -C,O enolate species; (3) net addition of the metal-coordinated enolate to the nitrile; and (4) C(sp 2 )–N(sp 2 ) reductive elimination. These mechanistic studies also highlight the influence of base choice on precatalyst activation in such benzofuran syntheses and the impact of RCN electronics on overall catalytic turnover in the formation of NH-indoles, as well as enabling catalyst speciation and NMR spectroscopic resting state determination. Guided by our mechanistic results, an electron-poor variant of meso -PAd2-DalPhos (i.e., meso -L9 ) was synthesized to promote challenging C(sp 2 )–( O -enolate) reductive elimination furnishing 2-substituted benzofurans, while an electron-rich variant (i.e., meso -L10 ) was employed to prevent competitive C(sp 2 )–( O -enolate) reductive elimination en route to 3-acyl-2-substituted NH-indoles.
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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 | 0.002 |
| 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".