Highly Enantioselective Organocatalysis with Bidentate Halogen Bond Donors
Bibliographic record
Abstract
As the employment of "non-classical" non-covalent interactions like halogen bonding (XB) in asymmetric catalysis is still at a very early stage, there are significant challenges to overcome. In some reported cases, the relevance of halogen bonding to the catalytic action is unclear, while in others, catalyst activity is limited. Herein, we present the second generation of a bidentate iodine(I)-based halogen bond donor as a modifiable and highly active chiral halogen bonding catalyst. With these modified derivatives, high stereocontrol of up to 98% ee could be achieved in a model Mukaiyama aldol reaction for a range of different substrates. Importantly, the crucial role of halogen bonding in this catalytic process was demonstrated by the low performance of the non-iodinated variants and by DFT calculations. The latter also indicate that the stereoinduction is based on the imposed orientation of the substrates towards each other.
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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) | 0.001 | 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 | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".