Heteroaromatics: The Cheon Synthesis of Rutaecarpine
Cunde Wang of Yangzhou University assembled (J. Org. Chem. 2016, 81, 7970. DOI: 10.1021/acs.joc.6b01259) the furan 3 by combining the aldehyde 2 with the donor-acceptor substituted cyclopropane 1. Qiang Liu of Lanzhou University and Li-Zhu Wu of constructed (Chem. Eur. J. 2016, 22, 13794. DOI: 10.1002/chem.201602053) the furan 5 by adding the α-chloroketone 4 to styrene.
Using a borrowed hydrogen strategy, Ken-ichi Shimizu of Hokkaido University prepared (Org. Chem. Front. 2016, 3, 846. DOI: 10.1039/C6QO00165C) the pyrrole 8 by combining 6 with 7. Frédéric Lamaty of the Université de Montpellier exposed (Tetrahedron 2016, 72, 7462. DOI: 10.1016/j.tet.2016.09.059) the product from the cyclization of 9 to base, leading to 10.
Scott D. Rychnovsky of the University of California, Irvine developed (J. Org. Chem. 2016, 81, 10376. DOI: 10.1021/acs.joc.6b01370) a simple modular synthesis of the pyridine 13, adding 12 in a conjugate sense to 11, then ozonizing the adduct. Wenbin Yi of the Nanjing University of Science and Technology and Wei Zhang of the University of Massachusetts Boston established (Org. Lett. 2016, 18, 5640. DOI: 10.1021/acs.orglett.6b02883) a related strategy, adding 15 in a conjugate sense to 14 to give 16. Maddi Sridhar Reddy of the Central Drug Research Institute cyclized (Chem. Commun. 2016, 52, 13475. DOI: 10.1039/C6CC08081B) 17 with tosyl azide to give 18. Milan Pour of Charles University in Prague reported (Adv. Synth. Catal. 2016, 358, 2912. DOI: 10.1002/adsc.201600412) related results. Ryo Takeuchi of Aoyama Gakuin University combined (J. Org. Chem. 2016, 81, 5393. DOI: 10.1021/acs.joc.6b00668) 20 with the diyne 19, leading to 21 with high regioselectivity.
Mei Guan and Yong Wu of Sichuan University showed (Synlett 2016, 27, 2485. DOI: 10.1055/s-0035-1562517) that 22 could be cyclized to the isatin 23. John E. Dueber and Richmond Sarpong of the University of California, Berkeley and Jin-Quan Yu of Scripps/La Jolla used (Angew. Chem. Int. Ed. 2016, 55, 11824. DOI: 10.1002/anie.201605475) remote C-H functionalization to convert 24 to indole 25. Quangxun Li and Zhuo Tang of the Chengdu Institution of Biology observed (Org. Lett. 2016, 18, 4526. DOI: 10.1021/acs.orglett.6b02133) that the addition of 27 to 26 led to 28 with high regioselectivity. Philip Wai Hong Chan of Monash University found (Adv. Synth. Catal. 2016, 358, 1385. DOI: 10.1002/adsc.201600011) that a gold catalyst could cyclize 29 to 30.
Rutaecarpine (33) was isolated from the dried unripe fruit of Evodia rutaecarpa Benth (吳茱萸, wu zhu yu), long used in traditional Chinese medicine. Cheol-Hong Cheon of Korea University developed (Org. Lett. 2016, 18, 5280, DOI: 10.1021/acs.orglett.6b02597; J. Org. Chem. 2016, 81, 7917, DOI: 10.1021/acs.joc.6b01621; Adv. Synth. Catal. 2016, 358, 1566, DOI: 10.1002/adsc.201600155) the imino-Stetter cyclization of 31 to 32. Reduction followed by ring closure completed the synthesis of 33.