Remarkable asymmetric induction from remote stereocenters in conjugate addition chemistry for the synthesis of alkyl‐branched α, ω‐diaminoazelates
Bibliographic record
Abstract
Abstract Conjugate addition of aryl Grignard reagents to (2 S , 5 E , 8 S )‐di‐ tert ‐butyl 4‐oxo‐2,8‐bis‐[ N ‐(PhF)amino]non‐5‐enedioate ( 6 , PhF = 9‐(9‐phenyl‐fluorenyl)) in THF proceeded with complete chemoselectivity and >9:1 stereoselectivity to provide predominantly (2 S ,6 S ,8 S )‐6‐aryl 4‐oxo‐2,8‐diamino‐azelates 7 . In the presence of magnesium dibromide, diastereoselectivity in the addition of PhMgBr to enone 6 was improved to 15:1 in favor of the 6 S ‐isomer. Although lower chemoselectivity and stereoselectivity were obtained from the analogous reaction of 6 with isopropyl magnesium bromide in the absence of MgBr 2 , both were improved significantly when the addition reaction was performed in the presence of MgBr 2 . In contrast, the corresponding higher‐order cyanocuprates reacted with low diastereoselectivity on 6 by a 1,4‐addition pathway. In an attempt to identify the source of the high selectivity in the conjugate addition chemistry with 6 and Grignard reagents, the syntheses of enones 12 and 13 provided model systems in which one of the two amino carboxylate moieties of 6 was replaced by a branched alkyl substituent. Conjugate addition reactions on 12 and 13 demonstrated that chemoselectivity with Grignard reagents in the 1,4‐addition reaction was contingent on the presence of an amino carboxylate moiety near the ketone of the enone system. Furthermore, because diastereoselectivity with Grignard reagents was significantly lower in additions to amino enones 12 and 13 relative to diamino enone 6 , the presence of both amino carboxylate moieties has been highlighted as an important factor for remarkable asymmetric induction in the conjugate addition of Grignard reagents.
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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 | 0.001 |
| 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 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".