Palladium catalysed tandem cyclisation-anion capture processes. Part 3. Organoboron anion transfer agents
摘要:
The cyclisation-anion capture protocol has been applied to a wide range of starter and terminating species to effect regio-and stereo-specific mono-and bis-cyclisation processes in which a variety of organoboronderivatives function as anion transfer reagents. Direct capture (no cyclisation) is rarely a problem and it can usually be suppressed by modification of the reaction conditions. (C) 1997 Elsevier Science Ltd.
Observations on the intramolecular Heck reactions of aromatic chlorides using palladium/imidazolium salts
作者:Stephen Caddick、William Kofie
DOI:10.1016/s0040-4039(02)02340-7
日期:2002.12
The intramolecular Heck reaction of aromatic amines and ethers using palladium/imidazoliumsalts is described. The use of tetra-n-butylammonium halide salts facilitates the reactivity of aromatic chlorides. An unexpected and novel palladium-mediated cyclisation is also described leading to the formation of a tricyclic adduct.
A transition metal-free Heck-type cyclization/isomerization reaction has been developed. Mediated by potassiumtert-butoxide and phenanthroline a variety of benzofuran derivatives have been synthesized.
Controlled Synthesis of 2- and 3-Substituted Benzo[<i>b</i>]furans
作者:Tao Pei、Cheng-yi Chen、Lisa DiMichele、Ian W. Davies
DOI:10.1021/ol102123u
日期:2010.11.5
A controlled regioselective synthesis of either C-2 or C-3 substituted benzo[b]furans from readily accessible 1-(2-hydroxyphenyl)-2-chloroethanones is described. Addition of a range of Grignard reagents to the α-chloro ketones generates alkoxide intermediates, which can form either 2-substituted benzo[b]furans via a [1,2]-arylmigration or 3-substituted benzo[b]furans via a direct cyclization and dehydration
描述了从容易获得的1-(2-羟苯基)-2-氯乙酮的C-2或C-3取代的苯并[ b ]呋喃的受控区域选择性合成。在α-氯代酮中添加一系列格氏试剂可生成醇盐中间体,该中间体可通过[1,2]-芳基迁移形成2-取代的苯并[ b ]呋喃,或通过a形成3-取代的苯并[ b ]呋喃。直接环化和脱水序列。提出了一种温度依赖性的[1,2]-芳基迁移机制,用于形成2-取代的苯并[ b ]呋喃。
Palladium(II)-Catalyzed Transformation of 3-Alkylbenzofurans to [2,3′-Bibenzofuran]-2′(3′H)-ones: Oxidative Dimerization of 3-Alkylbenzofurans
作者:Beom Shin Cho、Young Keun Chung
DOI:10.1021/acs.joc.6b02864
日期:2017.2.17
An unprecedented oxidative dimerization by palladium catalysis has been developed using PhI(OPiv)2 as a by-standing oxidant. This provides a facile method for the synthesis of quaternary 2,3′-bibenzofuran-2′(3′)-ones from readily accessible substrates. A plausible mechanism involving a Pd(II)–Pd(IV) catalytic cycle is proposed; a trace amount of water is required for subsequent oxidation.