Metal-Mediated C–C Ring Construction: The Sun/Lin Synthesis of Huperzine A

Abstract

Zachary T. Ball of Rice University found (Chem. Sci. 2014, 5, 1401) that the on-bead performance of a designed Rh- peptide complex was markedly superior to the corre­sponding solution catalysis for the addition of 2 to 1 to give 3. Jin-Quan Yu of Scripps/La Jolla achieved (J. Am. Chem. Soc. 2014, 136, 8138) remarkable ee in the conversion of 4 to 5. Adriaan J. Minnaard of the University of Groningen developed (Adv. Synth. Catal. 2014, 356, 2061) practical conditions for enantioselective conjugate addi­tion– enolate trapping, converting 6 to 8. Alexandre Alexakis of the University of Geneva had reported (Org. Lett. 2014, 16, 118) related results. Jérôme Waser of the Ecole Polytechnique Fédérale de Lausanne assembled (J. Am. Chem. Soc. 2014, 136, 6239) the amino cyclopentane 11 by adding 9 to 10. Jean-Luc Vasse of the Université de Reims used (Org. Lett. 2014, 16, 1506) the Schwartz reagent to cyclize 12 to 13. Eric V. Johnston and Armando Córdova of the University of Stockholm combined (Angew. Chem. Int. Ed. 2014, 53, 3447) Pd and organocatalysis in a cascade of first oxi­dation of 14, then conjugate addition by 15, then cyclization to 16. Professor Alexakis found (Org. Lett. 2014, 16, 2006) that the enolate from con­jugate addition to 17 could be trapped with a nitroalkene 18 to give, after in situ Nef reaction, the 1,4-diketone 19. Fangzhi Peng and Zhihui Shao of Yunnan University added (Chem. Eur. J. 2014, 20, 6112) malonate to the nitro alkene 20 to give an inter­mediate that could be carried to the cyclohexanone 21. Masahisa Nakada of Waseda University devised (Tetrahedron Lett. 2014, 55, 1100) a cascade conjugate reduc­tion—intramolecular conjugate addition to cyclize 22 to 23. Hye-Young Jang of Ajou University dimerized (Synthesis 2014, 46, 1329) cinnamaldehyde 24 with nitrometh­ane to give the fully-substituted cyclohexanol 25. In a remarkable cascade transformation, Joëlle Prunet of the University of Glasgow used (Org. Lett. 2014, 16, 3300) the Zhang Ru catalyst to cyclize 26 to the taxol skeleton 27. In an even more remarkable transformation, Professor Nakada showed (Tetrahedron Lett. 2014, 55, 1597) that cascade conjugate addition– conjugate addition converted 28 to 29, having the rare chair- boat- chair skeleton of the biologically potent fusidic acid and brasilicardin A.