Heteroaromatic Construction: The Li Synthesis of Mycoleptodiscin A
Kyungsoo Oh of Chung-Ang University cyclized (Org. Lett. 2015, 17, 450. ) the chloro enone 1 with NBS to the furan 2. Hongwei Zhou of Zhejiang University acylated (Adv. Synth. Catal. 2015, 357, 389. ) the imine 3, leading to the furan 4.
H. Surya Prakash Rao of Pondicherry University found (Synlett 2014, 26, 1059. ) 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. ) the pyrrole 10 by adding the silane 9 to the enone 8.
Barry M. Trost of Stanford University developed (Org. Lett. 2015, 17, 1433. ) 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. ) 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. ) 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. ) 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. ) 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. ) 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. ) 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. ) a gold catalyst to add 30 to 29, leading to 31.
In the endgame of a synthesis (Angew. Chem. Int. Ed. 2015, 54, 6878. ) 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.