Stereoselective C–O Ring Construction: The Keck Synthesis of Bryostatin I
Bibliographic record
Abstract
Vladimir Gevorgyan of the University of Illinois, Chicago homologated (Angew. Chem. Int. Ed. 2011, 50, 2808) the ketone 1 to the epoxide 2 using cyanogen bromide. Manabu Abe of Hiroshima University optimized (J. Am. Chem. Soc. 2011, 133, 2592) the diastereoselectivity of the Paternò-Büchi addition of benzophenone 4 to the secondary allylic alcohol 3 to give 5. Debaraj Mukherjee of the Indian Institute of Integrative Medicine constructed (Org. Lett. 2011, 13, 576) the lactone 7 by adding acetate to 6, with remarkable regioselectivity and diastereoselectivity. Tristan H. Lambert of Columbia University employed (Org. Lett. 2011, 13, 740) cyclopropenium activation to cyclize the diol 8 to 9. Brian L. Pagenkopf of the University of Western Ontario designed (Org. Lett. 2011, 13, 572) a Co catalyst for the diastereoselective oxidative cyclization of 11 to 12. Goverdhan Mehta of the Indian Institute of Science, Bangalore, found (Tetrahedron Lett. 2011, 52, 1749) that the Z-diene 13 cyclized efficiently to give the cyclic ether 14. Fabien Gagosz of the Ecole Polytechnique found (J. Am. Chem. Soc. 2011, 133, 7696) that the protonated complex derived from the allene 15 abstracted a hydride from the distal benzyl group, leading to cyclization to 16. Haruhiko Fuwa of Tohoku University found (Org. Lett. 2011, 13, 1820) that the unsaturated thioester 17 cyclized under gentle acid catalysis. Unsaturated esters (not illustrated) can be cyclized under alkaline conditions (Tetrahedron Lett. 2011, 52, 1372). Malcolm D. McLeod of the Australian National University established (J. Org. Chem. 2011, 76, 1992) a combination of Escherichia coli-derived enzyme and an α-d-glucuronyl fluoride donor for converting an alcohol 19 to the corresponding glucuronide metabolite 20. En route to an improved synthesis of the schweinfurthins, potent antineoplastic agents, David F. Wiemer of the University of Iowa devised (J. Org. Chem. 2011, 76, 909) the cyclization/ benzyloxymethyl transfer cascade that transformed 21 into 22. The synthesis and biological activity of the bryostatins is developing into one of the great success stories of natural products chemistry. A key step in the total synthesis of bryostatin 1 25 designed (J. Am. Chem. Soc. 2011, 133, 744) by Gary E. Keck of the University of Utah was the Rainier cyclization of 23 to 24.
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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) | 0.002 | 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".