The synthesis of 3-substituted 1-methylpyrrolo[1,2-a]pyrazines and 3-substitutedisoquinolines was achieved by the intramolecular cyclisation of 2-acetyl-1-propargylpyrroles and 2-alkynylbenzaldehydes, respectively, in the presence of ammonia under microwave heating. The tandem imination/annulation of 2-alkynylbenzaldehydes was easily accomplished under standard conditions, while TiCl4 was used to
nucleophilic addition/annulation reaction of ortho-alkynylbenzaldehydes in the presence of methanol. The reactions of aryl-, trimethylsilyl- and diethoxymethyl-substituted alkynylbenzaldehydes occurred with complete regioselectivity in good to excellent yields undermicrowaveirradiation. The reactions of alkyl-substituted alkynylbenzaldehydes took place with good yields and high regioselectivity only when
Sonogashira reaction of aryl halides with propiolaldehyde diethyl acetal catalyzed by a tetraphosphine/palladium complex
作者:Mhamed Lemhadri、Henri Doucet、Maurice Santelli
DOI:10.1016/j.tet.2005.06.062
日期:2005.10
All-cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/[PdCl(C3H5)]2 efficiently catalyzes the Sonogashira reaction of propiolaldehyde diethyl acetal with a variety of aryl bromides and chlorides. A minor electronic effect of the substituents of the aryl bromide was observed. Similar reaction rates were observed in the presence of activated aryl bromides such as 4-trifluoromethylbromobenzene and deactivated
清一色顺-1,2,3,4-四(二苯基膦基)环戊烷/ [的PdCl(C 3 H ^ 5)] 2有效地催化丙醛二乙基乙缩醛与各种芳基溴化物和氯化物的Sonogashira反应。观察到芳基溴的取代基的电子效应较小。在活化的芳基溴化物(例如4-三氟甲基溴苯)和失活的芳基溴化物(例如溴苯甲醚)的存在下,观察到相似的反应速率。该反应的营业额最高可达到95,000。甚至芳基氯化物和杂芳基溴化物或氯化物也已被该催化剂成功地炔基化。此外,芳基卤化物上的各种取代基如氟,三氟甲基,乙酰基,苯甲酰基,甲酰基,硝基,二甲基氨基或腈是可容许的。
A one-pot conversion of ortho-alkynyl benzaldehydes into indolo[2,1-a]isoquinolines
作者:George A. Kraus、Jonathan Beasley
DOI:10.1016/j.tetlet.2013.07.162
日期:2013.10
The conversion of readily available 2-halobenzaldehydes into indolo[2,1-a]isoquinolines in two operations represents a very direct entry to this class of molecules. (C) 2013 Elsevier Ltd. All rights reserved.