The Effect of Strain on the Rh<sup>I</sup>‐Catalyzed Rearrangement of Allylamines
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Bibliographic record
Abstract
Abstract A multitude of challenges facing modern synthesis have an enamine component as part of a solution. Transition‐metal‐catalyzed rearrangement of allylamines to enamines has occupied a prominent place among catalytic transformations. Similar to more conventional synthetic approaches to enamine intermediates, this chemistry typically leads to the formation of ( E ) isomers. Recently, a Rh I ‐catalyzed rearrangement of N ‐allylaziridines to ( Z )‐ N ‐alkenylaziridines was reported with kinetic stereoselectivities between 75:25 and 95:5 ( Z / E ). This exciting result warranted a mechanistic explanation. Herein we describe the results of quantum chemical calculations [B3LYP/6‐31+G(d,p)‐LANL2DZ] aimed at evaluating competing mechanisms for this isomerization. We have compared and contrasted two mechanisms for the rearrangement: one that proceeds through an azametallocyclopentene intermediate and another through a hydrometalation/β‐hydride elimination. We find that the latter mechanism corresponds to the lower energy pathway, which, counterintuitively, exhibits a kinetic preference for the formation of products with ( Z ) C=C double bonds. A close correspondence between product ratios determined by simple Boltzmann distribution calculations based on these theoretical results and the previously reported ratios is observed. Lastly, we have examined whether the observed stereocontrol is exclusive to strained amines, and we find that the unique characteristics of the aziridine ring, compared to other amines, prove to be essential. Given the privileged status of the enamine functional group in synthesis, application of the “strain effect” in a range of metal‐catalyzed processes is expected to have broad consequences.
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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 | 0.002 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 it