Synthesis of Indoles via 6π-Electrocyclic Ring Closures of Trienecarbamates
摘要:
A new method for the preparation of indoles from readily available alpha-haloenones and alpha-(trialkylstannyl)enecarbamates is described. Following a Stille coupling, trienecarbamate 2 is electronically activated to undergo a facile 6pi-electrocyclic ring closure and subsequent oxidation to afford protected aniline 4. Upon deprotection and reductive amination, acid 5 underwent clean cyclization to N-acetylindole 6 (Ac2O, NEt3, 130 degrees C). This method has been used to construct a variety of substituted indoles that are not easily prepared by conventional indole annelation methods.
Synthesis of Indoles via 6π-Electrocyclic Ring Closures of Trienecarbamates
摘要:
A new method for the preparation of indoles from readily available alpha-haloenones and alpha-(trialkylstannyl)enecarbamates is described. Following a Stille coupling, trienecarbamate 2 is electronically activated to undergo a facile 6pi-electrocyclic ring closure and subsequent oxidation to afford protected aniline 4. Upon deprotection and reductive amination, acid 5 underwent clean cyclization to N-acetylindole 6 (Ac2O, NEt3, 130 degrees C). This method has been used to construct a variety of substituted indoles that are not easily prepared by conventional indole annelation methods.
Antitumor Agents. VII. Synthesis and Antitumor Activity of Novel Hexacyclic Camptothecin Analogs
作者:Masamichi Sugimori、Akio Ejima、Satoru Ohsuki、Kouichi Uoto、Ikuo Mitsui、Kensuke Matsumoto、Yasuyoshi Kawato、Megumi Yasuoka、Keiki Sato
DOI:10.1021/jm00045a007
日期:1994.9
pentacyclic derivatives of camptothecin were synthesized and evaluated for in vitro cytotoxic activity against P388, HOC-21, and QG-56 and in vivo antileukemic activity against P388 in mice. Hexacyclic compounds which have an additional 5-, 6-, or 7-membered ring cyclized at positions 7 and 9 of camptothecin were prepared by intramolecular cyclization of pentacyclic camptothecin derivatives or Friedländer
Synthesis of Indoles via 6π-Electrocyclic Ring Closures of Trienecarbamates
作者:Thomas J. Greshock、Raymond L. Funk
DOI:10.1021/ja060282o
日期:2006.4.1
A new method for the preparation of indoles from readily available alpha-haloenones and alpha-(trialkylstannyl)enecarbamates is described. Following a Stille coupling, trienecarbamate 2 is electronically activated to undergo a facile 6pi-electrocyclic ring closure and subsequent oxidation to afford protected aniline 4. Upon deprotection and reductive amination, acid 5 underwent clean cyclization to N-acetylindole 6 (Ac2O, NEt3, 130 degrees C). This method has been used to construct a variety of substituted indoles that are not easily prepared by conventional indole annelation methods.