Insertion of Imines and Carbon Monoxide into Manganese−Alkyl Bonds: Synthesis and Structure of a Manganese−α-Amino Acid Derivative
Bibliographic record
Abstract
Two new routes have been developed to generate manganese-chelated amides from imine and carbon monoxide building blocks. The reaction of (CO) 5 MnR (R = CH 3, Ph) with ( p -tolyl)(R 1 ) NR 2 (R 1 = H, t Bu; R 2 = alkyl, H) results in the generation of the cyclometalated imine complexes (CO) 4 Mn[η 2 -4-CH 3 -2-(C(R 1 ) NR 2 )-C 6 H 3 ] in 50−84% isolated yield. However, when the reaction of ( p -tolyl)(H)C NCH 3 with (CO) 5 MnCH 3 is performed in the presence of AlCl 3, the product of sequential carbon monoxide and imine insertion is generated in 35% yield: (CO) 4 Mn[η 2 -C(H)( p -tolyl)N(CH 3 )COCH 3 ]. The addition of PPh 3 to the latter complex results in replacement of a carbonyl ligand and formation of the isolable fac -(CO) 3 (PPh 3 )Mn[η 2 -C(H)( p -tolyl)N(CH 3 )COCH 3 ]. In an alternative route to metal-bound amides, the oxidative addition of the N-acyl iminium salt ( p -tolyl(H)C N(CH 3 )COPh + Cl - to (CO) 5 Mn - Na + has been found to lead to the generation of the product of subsequent CO insertion, (CO) 4 Mn[η 2 -COC(H)( p -tolyl)N(CH 3 )COPh]. The latter represents the first example of a acyl-bound transition-metal-chelated α-amino acid complex and has been characterized by X-ray crystallography. Preliminary reactivity studies demonstrate that (CO) 4 Mn[η 2 -COC(H)( p -tolyl)N(CH 3 )COPh] reacts with PPh 3 to generate the unchelated ci s -(CO) 4 (PPh 3 )Mn[COC(H)( p -tolyl)N(CH 3 )COPh], while reaction with NaBH 4 leads to the liberation of the amide ( p -tolyl)CH 2 N(CH 3 )COPh, rather than the amino acid residue.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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 source (direct Gemma or distilled Codex), 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".