Iodine-Mediated Electrophilic Cyclization of 2-Alkynyl-1-methylene Azide Aromatics Leading to Highly Substituted Isoquinolines and Its Application to the Synthesis of Norchelerythrine
Dirk Fischer, Hisamitsu Tomeba, Nirmal K. Pahadi, Nitin T. Patil, Zhibao Huo and Yoshinori Yamamoto*
*Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan, Email: yoshimail.tains.tohoku.ac.jp
D. Fischer, H. Tomeba, N. K. Pahadi, N. T. Patil, Z. Huo, Y. Yamamoto, J. Am. Chem. Soc., 2008, 130, 15720-15725.
DOI: 10.1021/ja805326f (free Supporting Information)
The reaction of 2-alkynyl-1-methylene azide aromatics with iodium donors gave 1,3-disubstituted 4-iodoisoquinolines in good yields. Electron-donating and withdrawing substituents on the aromatic ring were equally tolerated. At the alkyne terminus, electron-neutral or donating substituents are clearly favored. A short synthesis of norchelerythrine is described.
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norchelerythrine (CAS: 6900-99-8)