Synthesis of Enantioenriched Borylated Cyclopropanols from Photoexcited Acylsilanes
Bibliographic record
Abstract
Cyclopropanes have played an important role in helping drug candidates achieve clinical success. Incorporation of cyclopropanes in bioactive compounds can lead to improved physicochemical properties or bolstered binding affinities due to conformational restrictions that favor protein target engagement. Tremendous effort has focused on the enantioselective synthesis of functionalized cyclopropanes; however, limitations regarding functional group variety and their relative configurations on the ring call for the exploration of alternative synthetic approaches. Here, we present the synthesis of enantioenriched 1,1-siloxycyclopropylboronic esters from photoexcited β-boryl acylsilanes using a ring-contractive 1,2-boronate rearrangement strategy. Triplet energy transfer catalysis is effective in triggering the desired cyclization via α-siloxycarbene formation; however, an unexpected stereoablative energy transfer process was observed and investigated. An alternative approach using direct photoexcitation was thereby developed and enabled stereochemical information to be relayed with complete fidelity through the transformation. The functional utility of 1,1-siloxycyclopropylboronic esters is demonstrated through a series of orthogonal transformations at the oxygen and boronic ester handles.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".