The Synthetic Potential of Thiophenium Ylide Cycloadducts
Bibliographic record
Abstract
(3+2) cycloaddition reactions are undeniably one of the most robust and versatily synthetic tool in heterocyclic chemis-try. The classical 1,3-dipolar cycloaddition, which uses 1,3-dipoles, are however limited to three-atom sequences demonstrating stabilized formal charges in their Lewis structure. The scope of three-atom groupings possible in (3+2) cycloadditions can be greatly expanded by taking of advantage neutral three-atom components (TACs). These also pro-vide an additional degree of chemical possibilities by resulting in zwitterionic (3+2) cycloadducts adaptable to multiple outcomes depending on structure and conditions. In this article, the intramolecular (3+2) cycloaddition reaction between alkynyl sulfides (neutral TAC) and alkynes to provide key thiophenium ylide intermediates is first reported. These highly reactive intermediates provide access to highly substituted fused thiophenes following predictable chemical sequences. Structural features on the obtained thiophenes was found to be highly configurable by judicious choice of both alkynyl sulfide substitution and reaction conditions.
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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) | 0.002 | 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".