Aminolactone Chiral Modifiers for Heterogeneous Asymmetric\nHydrogenation: Corrected Structure of Pantoyl-Naphthylethylamine,\nIn-Situ Hydrogenolysis, and Scanning Tunneling Microscopy Observation\nof Supramolecular Aminolactone/Substrate Assemblies on Pt(111)
Bibliographic record
Abstract
As established by Baiker and co-workers,\npantoyl-naphthylethylamine (PNEA) is an efficient synthetic chiral\nmodifier for the asymmetric hydrogenation of ketopantolactone (KPL)\nto pantolactone on supported Pt catalysts. We report a scanning tunneling\nmicroscopy (STM) study of PNEA and PNEA-derived aminolactone species\non Pt(111) and a reassignment of the relative stereochemistry of the\nmodifier. Robust organic chemistry methods were used to establish\nthat the structure of PNEA is <i>R</i>,<i>S</i> rather than <i>R</i>,<i>R</i>. The dissociative\nchemisorption of a fraction of PNEA adsorbed on Pt(111) yields two\nfragments that we attribute to a process involving C–N bond\nscission. We show that C–N bond scission occurs under hydrogenation\nconditions on PNEA-modified Pt/Al<sub>2</sub>O<sub>3</sub> catalysts,\nforming the aminolactone amino-4,4-dimethyldihydrofuran-2-one (AF).\nSTM measurements on (<i>S</i>)-AF and 2,2,2-trifluoroacetophenone\ncoadsorbed on Pt(111) show the formation of isolated 1:1 complexes.\nIn contrast, measurements on coadsorbed (<i>S</i>)-AF and\nKPL show fluxional supramolecular AF/KPL assemblies. The possibility\nthat such assemblies contribute to the overall enantioselectivity\nobserved for PNEA-modified Pt catalysts is discussed.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.001 | 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 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".