Yb(OTf)3-Mediated Ring Opening of Functionalized Cyclopentane Epoxides with Aniline: Aspects of Regiochemistry and Stereochemistry
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The ring-opening reaction of cyclopentan-1-ol 2,3-epoxides bearing alkoxy and hydroxyl groups with aniline was studied in the presence of Yb(OTf) 3 in refluxing toluene.The syn-and anti-relationship of the alkoxy group has an influence on the regioselectivity of attack affording aniline adducts at the secondary or tertiary position.The antibiotic pactamycin 1 isolated in 1961 from a fermentation broth of Streptomyces pactum var.pactum, is a unique member of a handful of naturally occurring aminocyclopentitols 2 (Figure 1).It exhibits activity against bacterial and also as a cytotoxic agent against cancer cell lines. 3Among the several functional groups and unusual patterns of substitution is the presence of a 3-acetyl aniline moiety at C-3.A key reaction in our total synthesis of pactamycin 4 was the introduction of a 3-isopropenyl aniline through the highly regioselective ring opening of an epoxide spanning a secondary and a tertiary carbon center mediated by Yb(OTf) 3 (Scheme 1). 5 The same type of reaction allowed us to prepare a number of substituted aniline analogs of de-6-methylsalicylyl pactamycin and to study their biological activities (Figure 1). 6trigued by the exclusive formation of the aniline corresponding to ring opening at the secondary carbon atom as hoped for, we initiated a study of the ring-opening of stereoisomeric model cyclopentan-1-ol 2,3epoxides with aniline in the presence of Yb(OTf) 3 as a Lewis acid. 7‡ Dedicated to Professor Victor Snieckus wishing him the best in chemistry and in life.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.003 | 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