Three‐Component Synthesis of <i>γ</i>‐Amino Esters with <i>α</i>‐Quaternary Carbon Centers via NHC/Photoredox Dual Catalysis
Bibliographic record
Abstract
γ ‐Amino acid derivatives are important motifs in medicinal chemistry and have shown wide applicability as inhibitory neurotransmitters. An important class of these compounds feature α , α ‐disubstitution. However, established routes for the direct synthesis of γ ‐amino esters bearing α ‐quaternary centers are severely limited in both number of available routes and scope of the transformation. Herein a method is presented for the three‐component synthesis of α , α ‐disubstituted γ ‐amino esters via N‐heterocyclic carbene/photoredox dual catalysis. This reaction involves in situ formation of an acyl azolium ester which undergoes photocatalytic reduction to the key stabilized alkoxycarbonyl radical. This methodology is shown to be capable of synthesizing a wide variety of γ ‐amino esters with various α ‐quaternary centers in moderate to good yields, including a derivative of the drug loperamide. The diversity of products that can be synthesized facilitates the rapid generation of libraries of γ ‐amino acid derived compounds.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".