Synthesis of 3-substituted indazoles and benzoisoxazoles via Pd-catalyzed cyclization reactions: application to the synthesis of nigellicine
作者:Kiyofumi Inamoto、Mika Katsuno、Takashi Yoshino、Yukari Arai、Kou Hiroya、Takao Sakamoto
DOI:10.1016/j.tet.2007.01.010
日期:2007.3
Syntheses of 3-substituted indazoles and benzoisoxazoles were efficiently accomplished with the aid of Pd-catalyzed intramolecular carbon-nitrogen and carbon-oxygen bond formations. The catalyst system described herein allows the cyclization to proceed under very mild conditions and thus could be applied to a wide range of substrates with acid- or base-sensitive functional groups. A total synthesis for the indazole ring-containing natural product nigellicine is also described. (c) 2007 Elsevier Ltd. All rights reserved.