2,3‐Bis[( <i>R</i> )‐(1,1‐dimethylethyl)methylphosphino]‐Quinoxaline
Bibliographic record
Abstract
Abstract image [ 866081‐62‐1 ] C 18 H 28 N 2 P 2 (MW 334.38) InChI = 1S/C18H28N2P2/c1‐17(2,3)21(7)15‐16(22(8)18(4,5)6)20‐14‐12‐10‐9‐11‐13(14)19‐15/h9‐12H,1‐8H3/t21‐,22‐/m0/s1 InChIKey = DRZBLHZZDMCPGX‐VXKWHMMOSA‐N (reagent may be used as a chiral ligand for rhodium, palladium, copper, and silver complexes to perform enantioselective reductions, conjugate additions, and allylic alkylations) Alternate Name: QuinoxP*. Physical Data: mp 102–103°C; [α] D −54.3° ( c 1.00, CHCl 3 ); 1 H NMR (395.75 MHz, CDCl 3 ) δ 1.00–1.03 (m, 18 H ), 1.42–1.44 (m, 6 H ), 7.70–7.74 (m, 2 H ), 8.08–8.12 (m, 2 H ); 13 C NMR (99.45 MHz, CDCl 3 ) δ 4.77 (t, J = 4.1 Hz), 27.59 (t, J = 7.4 Hz), 31.90 (t, J = 7.4 Hz), 129.50, 129.60, 141.63, 165.12 (dd, J = 5.7, 2.4 Hz); 31 P NMR (202.35 MHz, CDCl 3 ) δ−17.7 (s); IR (KBr) 2950, 1470, 780 cm −1 ; HRMS (FAB) calcd. for C 18 H 29 N 2 P 2 (M + + H); 335.1809; found: 335.1826. Anal. calcd. for C 18 H 28 N 2 P 2 : C, 64.66; H, 8.44. Found: C, 64.57; H, 8.29. 1 Solubility: sol toluene, ether, THF, dichloromethane, hexane. Form Supplied in: orange solid; commercially available. Preparative Methods: a solution of n ‐BuLi (1.25 mL of 1.60 M hexane solution, 2.0 mmol) was added dropwise to a stirred solution of t ‐butylmethylphosphine–borane (236 mg, 2.0 mmol) in THF (4 mL) at −78 °C under nitrogen. After 15 min, a solution of 2,3‐dichloroquinoxaline (133 mg, 0.67 mmol) in THF (4 mL) was added in one portion with vigorous stirring and the mixture was warmed to rt during 1 h. After stirring for additional 3 h, tetramethylethylenediamine (1 mL) was added and stirring was continued for 2 h. The reaction was quenched with 1 M HCl and the mixture was extracted with hexane. The combined extracts were washed with 1 M HCl and brine, and dried over Na 2 SO 4 . The solvent was removed in vacuum and the residue was purified by chromatography on silica gel (hexane/EtOAc = 30/1) to give the desired product (179 mg, 8%) as an orange solid, which was further purified by recrystallization from hot MeOH (1.7 mL) to give orange cubes. 1 Handling, Storage, and Precautions : stable to air and moisture for more than 8 months.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.102 | 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".