Organic Chemistry Portal
Organic Chemistry Highlights

Monday, October 19, 2015
Douglass F. Taber
University of Delaware

Heteroaromatic Construction: The Li Synthesis of Mycoleptodiscin A

Kyungsoo Oh of Chung-Ang University cyclized (Org. Lett. 2015, 17, 450. DOI: 10.1021/ol5034354) the chloro enone 1 with NBS to the furan 2. Hongwei Zhou of Zhejiang University acylated (Adv. Synth. Catal. 2015, 357, 389. DOI: 10.1002/adsc.201400713) the imine 3, leading to the furan 4.

H. Surya Prakash Rao of Pondicherry University found (Synlett 2014, 26, 1059. DOI: 10.1055/s-0034-1380403) that under Blaise conditions, exposure of 5 to three equivalents of 6 led to the pyrrole 7. Yoshiaki Nishibayashi of the University of Tokyo and Yoshihiro Miyake, now at Nagoya University, prepared (Chem. Commun. 2014, 50, 8900. DOI: 10.1039/C4CC03000A) the pyrrole 10 by adding the silane 9 to the enone 8.

Barry M. Trost of Stanford University developed (Org. Lett. 2015, 17, 1433. DOI: 10.1021/acs.orglett.5b00279) the phosphine-mediated cyclization of 11 to an intermediate that on brief exposure to a Pd catalyst was converted to the pyridine 12. Nagatoshi Nishiwaki of the Kochi University of Technology added (Chem. Lett. 2015, 44, 776. DOI: 10.1246/cl.150045) the dinitrolactam 14 to the enone 13 to give the pyridine 15. Metin Balci of the Middle East Technical University assembled (Org. Lett. 2015, 17, 964. DOI: 10.1021/acs.orglett.5b00067) the tricyclic pyridine 18 by adding propargyl amine 17 to the aldehyde 16. Chada Raji Reddy of the Indian Institute of Chemical Technology cyclized (Org. Lett. 2015, 17, 896. DOI: 10.1021/ol503752k) the azido enyne 19 to the pyridine 20 by simple exposure to I2.

Björn C. G. Söderberg of West Virginia University used (J. Org. Chem. 2015, 80, 4783. DOI: 10.1021/acs.joc.5b00433) a Pd catalyst to simultaneously reduce and cyclize 21 to the indole 22. Ranjan Jana of the Indian Institute of Chemical Biology effected (Org. Lett. 2015, 17, 672. DOI: 10.1021/ol5036968) sequential ortho C-H activation and cyclization, adding 23 to 24 to give the 2-substituted indole 25. In a complementary approach, Debabrata Maiti of the Indian Institute of Technology Bombay added (Chem. Eur. J. 2015, 21, 8723. DOI: 10.1002/chem.201501208) 27 to 26 to give the 3-substituted indole 28. In a Type 8 construction, Nobutaka Fujii and Hiroaki Ohno of Kyoto University employed (Chem. Eur. J. 2015, 21, 1463. DOI: 10.1002/chem.201405903) a gold catalyst to add 30 to 29, leading to 31.

In the endgame of a synthesis (Angew. Chem. Int. Ed. 2015, 54, 6878. DOI: 10.1002/anie.201501021) of the orthoquinone Mycoleptodiscin A (34), Ang Li of the Shanghai Institute of Organic Chemistry was not able to cyclize 32 with Pd catalysis. Fortunately, the Cu-mediated cyclization was successful.

D. F. Taber, Org. Chem. Highlights 2015, October 19.