Carbon−Carbon Bond Formation Promoted by Adjacent Metal Centers: Regioselective Alkyne Insertions into a “Rh(μ-CH<sub>2</sub>)Ru” Moiety Yielding C<sub>3</sub>- and C<sub>5</sub>-Bridged Fragments
Bibliographic record
Abstract
The heterobinuclear complex [RhRu(CO) 3 (μ-CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 2 ) (dppm = Ph 2 PCH 2 PPh 2 ), generated in situ from the tetracarbonyl precursor, reacts with the alkynes, dimethyl acetylenedicarboxylate, hexafluoro-2-butyne, and diethyl acetylenedicarboxylate to give the C 3 -bridged products [RhRu(CO) 3 (μ-η 1:η 1 -C(R) C(R)CH 2 )(dppm) 2 ][CF 3 SO 3 ] (R = CO 2 CH 3 ( 3 ), CF 3 ( 4 ), CO 2 CH 2 CH 3 ( 5 )), in which the alkynes have inserted into the Rh−C bond of the bridging methylene group. Compound 2 also reacts with 2-butyn-1-al diethylacetal and 2-butyn-1-ol, producing the insertion products [RhRu(CO) 3 (μ-η 1:η 1 -C(CH 3 ) C(R)CH 2 )(dppm) 2 ][CF 3 SO 3 ] (R = CH(OEt) 2 ( 6 ), CH 2 OH ( 7 )) analogous to compounds 3 − 5 . The regiochemistry of alkyne insertion in both cases has been established by 2-D NMR spectroscopy; the methyl substituent is adjacent to Rh, and the oxygen-containing substituent is adjacent to the methylene group. Attempts to generate an isomer of 3 by the reverse sequence of methylene insertion into the Rh−C bond of the alkyne-bridged species [RhRu(CO) 3 (μ-η 1:η 1 -C(CO 2 CH 3 ) C(CO 2 CH 3 ))(dppm) 2 ][X] (X = BF 4 ( 8a ), CF 3 SO 3 ( 8b )) failed with no reaction occurring, although reaction of the dicarbonyl analogue, [RhRu(OSO 2 CF 3 )(CO) 2 (μ-η 1:η 1 -C(CO 2 CH 3 ) C(CO 2 CH 3 ))(dppm) 2 ], with CH 2 N 2 results in methylene insertion into the Rh−Ru bond to give [RhRu(OSO 2 CF 3 )(CO) 2 (μ-CH 2 )(μ-η 1:η 1 -C(CO 2 CH 3 ) C(CO 2 CH 3 ))(dppm) 2 ] ( 10 ). Reaction of 3 with trimethylamine- N -oxide results in loss of a carbonyl and a rearrangement of the C 3 -bridged group, affording [RhRu(CO) 2 (μ-η 1:η 3 -CHC(CO 2 CH 3 ) CH(CO 2 CH 3 ))(dppm) 2 ][CF 3 SO 3 ] ( 11 ). Propargyl alcohol reacts with 2, affording a double-insertion product [RhRu(CO) 2 (μ-η 2:η 4 -CH C(CH 2 OH)CH C(CH 2 OH)CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 12 ) with incorporation of two propargyl alcohol units in a head-to-tail arrangement. The structures of compounds 4, 8a, and 12 were determined by X-ray methods.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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; 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".