Studies on enolate chemistry of 8-thiabicyclo[3.2.1]- octan-3-one: enantioselective deprotonation and synthesis of sulfur analogs of tropane alkaloids
Bibliographic record
Abstract
Enantioselective deprotonation of 8-thiabicyclo[3.2.1]octan-3-one (1) with chiral lithium amides, followed by reactions with electrophiles affords sulfur analogs of tropane alkaloids of pyranotropane family. Thus, deprotonation of 1 with (S)-N-(diphenyl)methyl-1-phenylethylamine (11d), followed by the reaction of the resulting nonracemic enolate with benzaldehyde gives the corresponding aldol product as one diastereoisomer (exo, threo) and in high enanatiomeric purity (95% ee). Trimethylsilyl chloride, acetic anhydride, and acyl cyanides react readily with the lithium enolate to give the corresponding derivatives of 1, however common alkylating agents fail to provide C-alkylated products. The reaction with acyl cyanides derived from α,β-unsaturated carboxylic acids (e.g., cinnamoyl cyanide) can be utilized in synthesis of thia-analogs of tropane alkaloids physoperuvine and isobellendine (13, 15).Key words: enantioselective deprotonation, tropane alkaloids.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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; 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".