Regio‐ and Stereoselective 1,3‐Oxathiolane Formation in the Reaction of Thiolactones with Optically Active Oxiranes
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
Abstract The reactions of 3 H ‐isobenzofuran‐1‐thione ( 1 ) with ( S )‐2‐methyloxirane ( 2 ) and ( R )‐2‐phenyloxirane ( 6 ) in the presence of SiO 2 in anhydrous CH 2 Cl 2 led to two pairs of diastereoisomeric spirocyclic 1,3‐oxathiolanes, i.e. , 3 and 4 with a Me group at C(5′), and 7 and 8 with a Ph group at C(4′), respectively ( Schemes 2 and 3 ). In both cases, 3 H ‐isobenzofuran‐1‐one ( 5 ) was formed as a main product. The analogous reactions of 3,4‐dihydro‐2 H‐ [1]benzopyran‐2‐thione ( 9 ) and 3,4,5,6‐tetrahydro‐2 H ‐pyran‐2‐thione ( 14 ) with 2 and 6 yielded four pairs of the corresponding diastereoisomeric spirocyclic compounds 10 and 11, 12 and 13, 15 and 16 , and 18 and 19 , respectively ( Schemes 4–7 ). In the reaction of 14 with 6 , the 1,3‐oxathiolane 20 with a Ph group at C(2) was also formed. The structures of 3, 7, 8, 10, 19 , and 20 were established by X‐ray crystallography ( Figs. 1–4 ). In contrast to the thiolactones 1, 9 , and 14 , the thioesters 21a – 21d did not react with ( R )‐2‐phenyloxirane ( 6 ) either in the presence of SiO 2 or under more‐drastic conditions with BF 3 ⋅Et 2 O or SnCl 4 ( Scheme 8 ). The results show that spirocyclic 1,3‐oxathiolanes can be prepared from thiolactones with oxiranes. The nucleophilic attack of the thiocarbonyl S‐atom at the SiO 2 ‐activated oxirane ring proceeds with high regio‐ and stereoselectivity via an S N 2‐type mechanism.
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) | 0.000 | 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) | 0.000 | 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