1,3‐Oxathiolanes from the Reaction of Aromatic and Enolized Thioketones with Monosubstituted Oxiranes
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Bibliographic record
Abstract
Abstract The reactions of 4,4′‐dimethoxythiobenzophenone ( 1 ) with ( S )‐2‐methyloxirane (( S )‐ 2 ) and ( R )‐2‐phenyloxirane (( R )‐ 6 ) in the presence of a Lewis acid such as BF 3 ⋅Et 2 O, ZnCl 2 , or SiO 2 in dry CH 2 Cl 2 led to the corresponding 1 : 1 adducts, i.e. , 1,3‐oxathiolanes ( S )‐ 3 with Me at C(5), and ( S )‐ 7 and ( R )‐ 8 with Ph at C(4) and C(5), respectively. A 1 : 2 adduct, 1,3,6‐dioxathiocane (4 S ,8 S )‐ 4 and 1,3‐dioxolane ( S )‐ 9 , respectively, were formed as minor products ( Schemes 3 and 5, Tables 1 and 2 ). Treatment of the 1 : 1 adduct ( S )‐ 3 with ( S )‐ 2 and BF 3 ⋅Et 2 O gave the 1 : 2 adduct (4 S ,8 S )‐ 4 ( Scheme 4 ). In the case of the enolized thioketone 1,3‐diphenylprop‐1‐ene‐2‐thiol ( 10 ) with ( S )‐ 2 and ( R )‐ 6 in the presence of SiO 2 , the enesulfanyl alcohols (1′ Z ,2 S )‐ 11 and (1′ E ,2 S )‐ 11 , and (1′ Z ,2 S )‐ 13 , (1′ E ,2 S )‐ 13 , (1′ Z ,1 R )‐ 15 , and (1′ E ,1 R )‐ 15 , respectively, as well as a 1,3‐oxathiolane ( S )‐ 14 were formed ( Schemes 6 and 8 ). In the presence of HCl, the enesulfanyl alcohols (1′ Z ,2 S )‐ 11 , (1′ Z ,2 S )‐ 13 , (1′ E ,2 S )‐ 13 , (1′ Z ,1 R )‐ 15 , and (1′ E ,1 R )‐ 15 cyclize to give the corresponding 1,3‐oxathiolanes ( S )‐ 12 , ( S )‐ 14 , and ( R )‐ 16 , respectively ( Schemes 7, 9 , and 10 ). The structures of (1′ E ,2 S )‐ 11 , ( S )‐ 12 , and ( S )‐ 14 were confirmed by X‐ray crystallography ( Figs. 1 – 3 ). These results show that 1,3‐oxathiolanes can be prepared directly via the Lewis acid‐catalyzed reactions of oxiranes with non‐enolizable thioketones, and also in two steps with enolized thioketones. The nucleophilic attack of the thiocarbonyl or enesulfanyl S‐atom at the Lewis acid‐complexed oxirane ring proceeds with high regio‐ and stereoselectivity via an S n 2‐type mechanism.
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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) | 0.001 | 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 it