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Monday, December 10, 2012
Douglass F. Taber
University of Delaware

Organocatalyzed Carbocyclic Construction: (+)-Roseophilin (Flynn) and (+)-Galbulin (Hong)

Armido Studer of Wilhems-University Münster effected (Chem. Commun. 2012, 48, 5190. DOI: 10.1039/C2CC31501G) enantioselective conjugate addition of 2 to 1, leading to the cyclopropane 3. Karl Anker Jørgensen of Aarhus University devised (J. Am. Chem. Soc. 2012, 134, 2543. DOI: 10.1021/ja211878x) a route to cyclobutanes based on enantioselective addition of 5 to the nitroalkene 4. Jose L. Vicario of the Universidad del País Vasco reported (Angew. Chem. Int. Ed. 2012, 51, 4104. DOI: 10.1002/anie.201200269) a similar procedure.

Benjamin List of the Max-Planck-Institute Mülheim epoxidized (Adv. Synth. Catal. 2012, 354, 1701. DOI: 10.1002/adsc.201200072) cyclopentenones such as 7 with high ee. Lutz H. Gade of the Universität Heidelberg observed (J. Am. Chem. Soc. 2012, 134, 2946. DOI: 10.1021/ja211859w) high ee in the benzylation of 9. Cheng Ma of Zhejiang University formylated (J. Org. Chem. 2012, 77, 2959. DOI: 10.1021/jo202633c) cyclopentanone, then condensed the resulting aldehyde 12 with 13 to give 14. Hao Xu of Georgia State University cyclized (Org. Lett. 2012, 14, 858. DOI: 10.1021/ol203375y) 15 to the cyclopentenone 16.

(+)-Rosephilin 19 inhibits several phosphatases. Bernard L. Flynn of Monash University prepared (Org. Lett. 2012, 14, 1740. DOI: 10.1021/ol300332b) the carbocyclic core of 19 by cyclizing 17 to the cyclopentenone 18.

Masanori Yoshida of Hokkaido University designed (J. Org. Chem. 2011, 76, 8513. DOI: 10.1021/jo201429w) a very simple organocatalyst for the enantioselective conjugate addition of 21 to 20. Samuel H. Gellman of the University of Wisconsin showed (Org. Lett. 2012, 14, 2582. DOI: 10.1021/ol3008815) that nitromethane could be added to 23 with high ee. Hiroaki Sasai of Osaka University effected (Angew. Chem. Int. Ed. 2012, 51, 5423. DOI: 10.1002/anie.201201542) the enantioselective cyclization of the prochiral 25. Ying-Chun Chen of Sichuan University found (Angew. Chem. Int. Ed. 2012, 51, 4401. DOI: 10.1002/anie.201200248) that the diene 27 could be converted to 29 by way of the intermediate trienamine.

Bor-Cherng Hong of the National Chung Cheng University observed (Chem. Commun. 2012, 48, 2385. DOI: 10.1039/C2CC16682H) that under organocatalysis, only one enantiomer of 31 would add to 30, delivering 32 in high ee. Aromatization of 32 led to (+)-Galbulin (33).

D. F. Taber, Org. Chem. Highlights 2012, December 10.