BINAPS - An axially chiral <i>P</i>,<i>S</i>-heterodonor ligand for asymmetric catalysis based on binaphthalene backbone
Bibliographic record
Abstract
The chelating P,S-heterodonor ligand 2-diphenylphosphanyl-1,1'-binaphthalene-2'-thiol (11) (BINAPS), which features a chiral axis as the unique stereogenic element, has been prepared in both racemic and enantiopure form through a multistep reaction sequence using 2,2'-dihydroxy-1,1'-binaphthalene (BINOL) as the starting material. The reaction sequence is completely stereoconservative and (S)-11 is obtained with no loss of enantiopurity from pure (S)-BINOL. (R)-11 can be alternatively obtained by resolution of racemic 11 using the chiral (S)-benzylaminato Pd(II)-complex 19 as the resolving agent. The S-methyl or the S-i-propyl derivatives 14 have been used as chiral ligands in the Rh(I)-catalyzed asymmetric hydroformylation of styrene and in the hydrogen transfer reduction of acetophenone with modest success (up to 20% ee). In the presence of suitable Pd-complexes the same ligands provide higher ees in the hydrosilylation of styrene (50% ee) and in the allylic alkylation of 1,3-diphenylprop-2-enyl acetate (60% ee).Key words: heterodonor ligands, binaphthalene derivatives, enantioselective catalysis, transition metal catalysts, allylic alkylation.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".