Metal-Mediated Carbocyclic Construction: The Chen Synthesis of Ageliferin

Djamaladdin G. Musaev and Huw M. L. Davies of Emory University designed (J. Am. Chem. Soc. 2011, 133, 19198. DOI: 10.1021/ja2074104) a Rh catalyst that added 2 to 1 to give 3 with high dr and ee. Shunichi Hashimoto of Hokkaido University reported (Angew. Chem. Int. Ed. 2011, 50, 6803. DOI: 10.1002/anie.201101905) a Rh catalyst that would add the α-diazo ester 5 to a terminal alkyne 4 to give the cyclopropene 6 in high ee.

Gaëlle Blond and Jean Suffert of the Université de Strasbourg cyclized (Adv. Synth. Catal. 2011, 353, 3151. DOI: 10.1002/adsc.201100465) the alkyne 7, then coupled the Pd intermediate with a terminal alkyne 8 to give the cyclobutane 9. Nuno Maulide of the Max-Planck-Institut Mülheim ionized (Angew. Chem. Int. Ed. 2011, 50, 12631. DOI: 10.1002/anie.201106321) the lactone 10 to a prochiral intermediate, that could then be coupled with 11 to give either diastereomer of 12 in high ee.

Martin Hiersemann of the Technische Universität Dortmund devised (Org. Lett. 2011, 13, 4438. DOI: 10.1021/ol201795w) a Pd catalyst for the selective cyclization of 13 to 14. Naoya Kumagai and Masakatsu Shibasaki of the Institute of Microbial Chemistry, Tokyo effected (Angew. Chem. Int. Ed. 2011, 50, 7616. DOI: 10.1002/anie.201102114) the enantioselective Conia ene cyclization of 15 to 16. Barry M. Trost of Stanford University developed (J. Am. Chem. Soc. 2011, 133, 19483. DOI: 10.1021/ja207550t) an enantioselective variant of the trimethylenemethane cycloaddition of 18 to 17 to give 19. In the course of a synthesis of (-)-Oseltamivir phosphate, Masahiko Hayashi of Kobe University found (J. Org. Chem. 2011, 76, 5477. DOI: 10.1021/jo200698g) conditions for the enantioselective oxidation of 20 to 21.

Quanrui Wang of Fudan University and Andreas Goeke of Givaudan Fragrances (Shanghai) cyclized (J. Org. Chem. 2011, 76, 5825. DOI: 10.1021/jo200416d) the propargylic acetate 22 to the cyclohexenone 23. Chuang-chuang Li, Tuoping Luo and Zhen Yang of Peking University cyclized (J. Am. Chem. Soc. 2011, 133, 14944. DOI: 10.1021/ja206837j) the diyne 24 to the lactone 25. Hiromitsu Takayama of Chiba University used (Angew. Chem. Int. Ed. 2011, 50, 8025. DOI: 10.1002/anie.201103550) the silyl tether of 26 to constrain the diastereomeric outcome of the cyclization to 27. E. J. Corey of Harvard University showed (J. Am. Chem. Soc. 2011, 133, 9724. DOI: 10.1021/ja204142n) that InI₃ catalyzed the conversion of 28 to 29, with the secondary OH directing the absolute course of the cyclization

En route to Ageliferin, Chuo Chen of UT Southwestern Medical Center oxidized (J. Am. Chem. Soc. 2011, 133, 15350. DOI: 10.1021/ja207386q) 30 to a radical, that cyclized to 31. The secondary aminated center directed the cyclization cleanly, but in the opposite sense to that which they had expected, so the final product was ent-Ageliferin 32.