Enantioselective Cyclopropanation Using Dioxaborolane Ligands
Bibliographic record
Abstract
Enantiopure cyclopropanes are important subunits found in several natural products. This chapter will highlight our efforts to design a stoichiometric chiral additive for the enantioselective cyclopropanation of allylic alcohols (Eq 1). Some preliminary mechanistic features of the cyclopropanation reaction in the presence of dioxaborolane 1 and related analogs will also be presented. I. Synthesis The chiral dioxaborolane 1 can be prepared using either one of two procedures. Originally, this dioxaborolane was generated under dehydrating conditions by using two readily available precursors : N, N, N', N'-tetramethyl-L-tartaramide 2 and butylboronic acid 3 (Eq 2). These two precursors are commercially available, or easily prepared from tartaric acid (in the case of the tartaramide (44)) and from butyl magnesium bromide and trimethyl borate (in the case of the butylboronic acid (45)). It is not that convenient to store alkylboronic acids since these compounds are quite oxygen-sensitive. Indeed, 3 is gradually oxidized to generate
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How this classification was reachedexpand
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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 | 0.001 |
| 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 teacher head, 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".