Heteroaromatic Construction: The Sperry Synthesis of (+)-Terreusinone

Akio Saito and Yuji Hanzawa of Showa Pharmaceutical University found (Tetrahedron Lett. 2011, 52, 4658. DOI: 10.1016/j.tetlet.2011.06.117) that an alkynyl keto ester 1 could be oxidatively cyclized to the furan 2. Eric M. Ferreira of Colorado State University showed (Org. Lett. 2011, 13, 5924. DOI: 10.1021/ol202649j) that depending on the conditions, a Pt catalyst could cyclize 3 to either 4 or 5.

Shunsuke Chiba of Nanyang Technological University used (J. Am. Chem. Soc. 2011, 133, 13942. DOI: 10.1021/ja206580j) Cu catalysis for the oxidation of 6 to the pyrrole 7. Vladimir Gevorgyan of the University of Illinois at Chicago devised (Org. Lett. 2011, 13, 3746. DOI: 10.1021/ol2014347) a convergent assembly of the pyrrole 10 from the alkyne 8 and the alkyne 9.

Dale L. Boger of Scripps La Jolla extended (J. Am. Chem. Soc. 2011, 133, 12285. DOI: 10.1021/ja204856a) the scope of the Diels-Alder addition of the triazine 11 to an alkyne 12, to give the pyridine 13. Tomislav Rovis, also of Colorado State University, used (Chem. Commun. 2011, 47, 11846. DOI: 10.1039/C1CC15248C) a Rh catalyst to add an alkyne 15 to the oxime 14, to give the pyridine 16. Sensuke Ogoshi of Osaka University, under Ni catalysis, added (J. Am. Chem. Soc. 2011, 133, 18018. DOI: 10.1021/ja208162w) a nitrile 18 to the diene 17 to give the pyridine 19. Alexander Deiters of North Carolina State University showed (Org. Lett. 2011, 13, 4352. DOI: 10.1021/ol201682k) that the complex tethered diyne 20 combined with 21 with high regiocontrol, to give 22.

Yong-Min Liang of Lanzhou University prepared (J. Org. Chem. 2011, 76, 8329. DOI: 10.1021/jo201514q) the indole 24 by cyclizing the alkyne 23. Xiuxiang Qi and Kang Zhao of Tianjin University found (J. Org. Chem. 2011, 76, 8690. DOI: 10.1021/jo2012187) that the enamine 25 could be oxidatively cyclized to the indole 26. Kazuhiro Yoshida and Akira Yanagisawa of Chiba University established (Org. Lett. 2011, 13, 4762. DOI: 10.1021/ol201510u) that ring-closing metathesis converted the keto ester 27 to the indole 28. Alessandro Palmieri and Roberto Ballini of the Università di Camerino observed (Adv. Synth. Catal. 2011, 353, 1425. DOI: 10.1002/adsc.201000965) that the pyrrole 30 spontaneously added to the nitro acrylate 29, to give an adduct that cyclized to 31 on exposure to acid.

Jonathan Sperry of the University of Auckland effected (Org. Lett. 2011, 13, 6444. DOI: 10.1021/ol2027398) tandem Sonogashira/Larock coupling of 32 with two equivalents of the alkyne 33, to give 34. Further cyclization followed by oxidation delivered (+)-Terreusinone (35).