C-N Ring Construction: The Yang Synthesis of (-)-Alstoscholarisine A
Shifa Zhu of the South China University of Technology took advantage (Org. Lett. 2016, 18, 5208. DOI: 10.1021/acs.orglett.6b02429) of the rearrangement of 1 to the corresponding furyl carbene, adding it to 2 to construct the aziridine 3. Keiji Maruoka of Kyoto University demonstrated (Org. Lett. 2016, 18, 6252. DOI: 10.1021/acs.orglett.6b03003) the UV-mediated [2+2] addition of 4 to the alkene 5, leading to the azetidine 6 with high stereocontrol.
Shin Kamijo of Yamaguchi University devised (Angew. Chem. Int. Ed. 2016, 55, 9695. DOI: 10.1002/anie.201603810) a photochemically-promoted protocol for C-H iminomethylation, combining 8 and 9 to convert 7 into 10. Hui Lv, Xiu-Qin Dong and Xumu Zhang of Wuhan University used (J. Am. Chem. Soc. 2016, 138, 9017. DOI: 10.1021/jacs.6b03596) asymmetric hydroformylation to cyclize 11 to pyrrolidine 12. Nisar Ullah of the King Fahd University of Petroleum and Materials and Yixin Lu of the National University of Singapore cyclized (Eur. J. Org. Chem. 2016, 4298. DOI: 10.1002/ejoc.201600794) the product from adding a protected glycine to 13, to give, after reduction, the proline derivative 14. Jian-Jun Feng and Junliang Zhang of East China Normal University prepared (Angew. Chem. Int. Ed. 2016, 55, 10844. DOI: 10.1002/anie.201605530) 17 by adding the aziridine 15 to the allene 16.
Qing Liu and Hui Liu of the Shandong University of Technology cyclized (Org. Lett. 2016, 18, 3774. DOI: 10.1021/acs.orglett.6b01787) 18 to 19. Aryl cycloalkenes such as 19 participate efficiently in Shi asymmetric epoxidation. Yu Zhou and Hong Liu of the Shanghai Institute of Materia Medica assembled (Adv. Synth. Catal. 2016, 358, 1864. DOI: 10.1002/adsc.201600136) 22 by adding 21 to 20. Till Opatz of the University of Mainz effected (Org. Biomol. Chem. 2016, 14, 7084. DOI: 10.1039/C6OB01308B) conjugate addition of 23 to 24, leading to 25. Huawu Shao of the Chengdu Institute of Biology cyclized (Tetrahedron 2016, 72, 3994. DOI: 10.1016/j.tet.2016.05.023) the ribose derivative 26 with acetone and benzylamine to the piperidine 27.
Srihari Pabbaraja and Yadav Jhillu Singh of the Academy of Scientific and Innovative Research employed (Tetrahedron Lett. 2016, 57, 4456. DOI: 10.1016/j.tetlet.2016.08.054) a Cu catalyst to cyclize 28 to 29. Building on their previous results, Bernardo Herradón and Enrique Mann of the Instituto de Química Orgánica General designed (Tetrahedron 2016, 72, 4617. DOI: 10.1016/j.tet.2016.06.023) the cascade cyclization of 30 to the tricyclic 31.
(-)-Alstoscholarisine A (33), isolated from the tropical evergreen tree Alstonia scholaris, shows promising activity in promoting adult neuronal stem cell proliferation. Yu-Rong Yang of the Kunming Institute of Botany set (J. Am. Chem. Soc. 2016, 138, 2560. DOI: 10.1021/jacs.6b00625) the absolute configuration of 33 by cyclizing 31 to 32.