Mild Palladium-Catalyzed Regioselective Direct Arylation of Azoles Promoted by Tetrabutylammonium Acetate
作者:Fabio Bellina、Marco Lessi、Chiara Manzini
DOI:10.1002/ejoc.201300704
日期:2013.9
A mild, general, and convenient palladium-catalyzed direct arylation of the 5-position of azoles with aryl bromides, efficiently promoted by tetrabutylammonium acetate, is described. 1-Methylpyrazole, oxazole, and thiazole reacted at 70 °C in N,N-dimethylacetamide by using Pd(OAc)2 as the catalyst precursor. Electron-poor and -rich functional groups, including the free hydroxy group, are well tolerated
描述了一种温和、通用且方便的钯催化的 5-位唑类与芳基溴化物的直接芳基化反应,由乙酸四丁铵有效促进。通过使用 Pd(OAc)2 作为催化剂前体,1-甲基吡唑、恶唑和噻唑在 N,N-二甲基乙酰胺中在 70 °C 下反应。贫电子和富电子官能团,包括游离羟基,在亲电伙伴中具有良好的耐受性。通过将反应温度提高到 110 °C,也可以非常有效地获得各种 5-芳基-1-甲基咪唑。这种无配体方案已成功应用于两种生物活性天然化合物 balsoxin 和 texaline 的一锅合成,从恶唑开始,通过 5 位和 2 位的顺序直接芳基化。