Synthesis of 3-Iodoindoles by Electrophilic Cyclization of N,N-Dialkyl-2-(1-alkynyl)anilines
摘要:
A wide variety of N-alkyl-3-iodoindoles are readily prepared under very mild reaction conditions by the palladium/copper-catalyzed cross-coupling of N,N-dialkyl-o-iodoanilines and terminal alkynes, followed by electrophilic cyclization by I-2. Alkyl-, aryl-, and vinylic-substituted alkynes all undergo iodocyclization in excellent yields.
A palladium-catalyzed tandem cyclization/C-H functionalization of two alkynes was accomplished to construct a series of polycyclic functionalized indoles. A range of internal alkynes bearing synthetically useful functional groups were tolerated. A good regioselectivity was observed when alkyl-substituted alkynes were introduced into the reaction system, and a single product was obtained. Molecular oxygen was used as the terminal oxidant in the approach, rendering the reaction more sustainable.
A Novel Synthetic Route to 3-Sulfenyl- and 3-Selenylindoles by <i>n</i>-Bu<sub>4</sub>NI-Induced Electrophilic Cyclization
作者:Yu Chen、Chul-Hee Cho、Richard C. Larock
DOI:10.1021/ol8021287
日期:2009.1.1
3-Sulfenyl- and 3-selenylindoles are prepared In excellent yields by the palladium/copper-catalyzed crossing coupling of N,N-dialkyl-o-iodoanilines and terminal alkynes, followed by electrophilic cyclization with arylsulfenyl chlorides and arylselenyl chlorides in the presence of a stoichiometric amount of n-Bu4NI.
Synthesis of 3-Iodoindoles by the Pd/Cu-Catalyzed Coupling of <i>N,N</i>-Dialkyl-2-iodoanilines and Terminal Acetylenes, Followed by Electrophilic Cyclization
作者:Dawei Yue、Tuanli Yao、Richard C. Larock
DOI:10.1021/jo051549p
日期:2006.1.1
3-lodoindoles have been prepared in excellent yields by coupling terminal acetylenes with N,N-dialkyl-o-iodoanilines in the presence of a Pd/Cu catalyst, followed by an electrophilic cyclization of the resulting N,N-dialkyl-o-(1-alkynyl)anilines using I-2 in CH2Cl2. Aryl-, vinylic-, alkyl-, and silyl-substituted terminal acetylenes undergo this process to produce excellent yields of 3-iodoindoles. The reactivity of the carbon-nitrogen bond cleavage during cyclization follows the following order: Me > n-Bu, Me > Ph, and cyclohexyl > Me. Subsequent palladium-catalyzed.Sonogashira, Suzuki, and Heck reactions of the resulting 3-iodoindoles proceed smoothly in good yields.
An efficient, microwave-assisted, one-pot synthesis of indoles under Sonogashira conditions
作者:Yu Chen、Nataliya A. Markina、Richard C. Larock
DOI:10.1016/j.tet.2009.07.075
日期:2009.10
A microwave-assisted, one-pot, three-component coupling reaction for the synthesis of indoles has been developed. The reaction is carried out in two steps under standard Sonogashira coupling conditions from an N-substituted/N,N-disubstituted 2-iodoaniline and a terminal alkyne, followed by the addition of acetonitrile and an aryl iodide. A variety of polysubstituted indoles have been prepared in moderate to excellent yields using the present method. (C) 2009 Elsevier Ltd. All rights reserved.