Addition of P-H Bonds to Heterocumulenes
Bibliographic record
Abstract
In the pursuit of synthesising novel heteroatom-rich phosphorus analogues of ubiquitous ureas, thioureas and guanidines in a sustainable manner, an atom efficient hydrofunctionalisation approach was undertaken. Either by catalysis or catalyst-free (where viable), testing the addition of different P-H bond containing substrates to multiple bond containing heterocumulenes; isocyanates (RN=C=O), isothiocyanates (RN=C=S) and carbodiimides (RN=C=NR). A catalyst-free low solvent approach for the hydrophosphinylation of isocyanates and isothiocyanates is applicable to a range of phosphorus nucleophiles; including secondary phosphine oxides HP(O)R2 (R = Ph, iPr), phosphites HP(O)(OR)2 (R = Me, Et), and methyl phenylphosphinate. The procedure tolerated isocyanates and isothiocyanates featuring a wide range of substituents in moderate to excellent yields, and by using 4 eq. of 2-MeTHF solvent, solid substrates can be utilised. Facile scale-up and simple reaction conditions make this a straightforward and practical methodology. Low-coordinate Iron-based m-terphenyl precatalyst, 40 performed double hydrophosphination of isocyanates with primary phosphines, RPH2 (R = Fc, Ad) and additionally formed novel diinsertion-cyclisation products (52 or 55). These are formed when less bulky aryl isocyanates are utilised with alkyl isocyanates only forming mono-insertion hydrophosphination products. Selectivity for diinsertion-cyclisation products can be achieved by decreasing solvent (C6D6) quantity, increasing isocyanate concentration and increasing temperature. Additionally, 40 is an efficient precatalyst for single (with HPPh2) and double (with FcPH2) hydrophosphination of carbodiimides. Under moderate conditions hydrophosphination reactions undergo near quantitative (HPPh2) and moderate to excellent (FcPH2) conversions for a range of carbodiimides, with only 1 of 8 possible isomers selectively being formed for single hydrophosphination.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.014 |
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; both teacher heads agree on what is shown here.
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".