Other Methods for C–C Ring Construction: Pinolinone (Bach), Agelastatin A (Batey), Panaginsene (Lee), Salvileucalin D, Salvileucalin C (Ding), ent-Codeine (Hudlicky), Walsucochin B (Xie/Shi)
Bibliographic record
Abstract
Thorsten Bach of the Technische Universität München used (Chem. Commun. 2014, 50, 3353) the chiral medium-mediated photochemical 2+2 cycloaddition that he developed to prepare 3 by combining 1 with 2. Oxidative cleavage led to (−)-pinolinone 4. Robert A. Batey of the University of Toronto rearranged (Angew. Chem. Int. Ed. 2013, 52, 10862) furfural 5 in the presence of 6 to give the enone 7. Acylation followed by intramolecular conjugate addition delivered agelastatin A 8. Hee-Yoon Lee of KAIST prepared (Org. Lett. 2014, 16, 2466) the tosylhydrazone Na salt 9 from citronellal. Thermolysis led, via a dialkyl diazo intermediate, to the tricyclic 10. Direct comparison of synthetic material with the natural product panaginsene 11 enabled the assignment of the relative configuration of the pendant methyl group. Hanfeng Ding of Zhejiang University eliminated (Org. Lett. 2014, 16, 3376) HBr from 12 to give, after rearrangement, the cycloheptadiene salvileucalin D 13. Irradiation converted 13 to the cyclobutene salvileucalin C 14. In a recent chapter of his continuing work on the morphine alkaloids, Tomas Hudlicky of Brock University described (Adv. Synth. Catal. 2014, 356, 333) the intramolecular [3+2] cycloaddition of the nitrone derived from 15 to give 16. This was readily carried on to ent-codeine 17. Xingang Xie and Xuegong She of Lanzhou University used (Org. Lett. 2014, 16, 1996) Shi epoxidation and Itsuno–Corey reduction to prepare 18 in enantiomerically-pure form. Cationic cyclization converted 18 to 19, that was oxidized to (−)-walsucochin B 20.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.015 | 0.005 |
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".