Nickel-catalyzed cross-couplings of 4-diethylphosphonooxycoumarins with organozinc reagents: an efficient new methodology for the synthesis of 4-substituted coumarins.
Nickel-catalyzed cross-couplings of 4-diethylphosphonooxycoumarins with organozinc reagents: an efficient new methodology for the synthesis of 4-substituted coumarins.
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DOI：
10.1002/chin.200218077
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发表时间：
2001-10
期刊：
影响因子：
--
通讯作者：
Jie Wu;Zhen Yang
中科院分区：
文献类型：
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作者：
Jie Wu;Zhen Yang
钯催化和镍催化的有机卤化物和三氟酸盐与有机金属试剂的交偶联反应在文献中是众所周知的。1近年来，合成界在镍催化的交叉偶联反应方面取得了重大进展，如有机硅烷与高价碘盐或磺胺盐的偶联；2芳基卤化物、乙烯基磷酸盐、乙烯基三酸酯和芳基甲磺酸与芳基硼酸（suzuki型偶联）、有机化合物（negishi型偶联）和Grignards （kumada型偶联）的偶联；3、多官能团芳基锌与伯烷基碘化物的偶联，4、二硫缩醛与格氏试剂的偶联。在之前的一篇论文中，我们描述了钯催化的4-甲酰基香豆素与乙炔或锌试剂的交叉偶联。这些反应使我们能够在温和的条件下以高产量生产多样化的4-炔基香豆素。在这封信中，我们报告了我们最近用镍(0)作为催化剂，将4-二乙基膦氧基香豆素与多种有机锌试剂偶联，以合成多种4-芳基和烷基香豆素的结果。虽然文献中已知的合成4-取代香豆素的方法多种多样，但大多数
The palladium-catalyzed and nickel-catalyzed crosscoupling reactions of organic halides and triflates with organometallic reagents are well-known in the literature. 1 Recently, the synthetic community has witnessed significant progress in the nickel-catalyzed cross-coupling reactions, such as the coupling of organostannane with hypervalent iodonium salts or sulfonium salts; 2 the coupling of aryl halides, vinyl phosphates, vinyl triflates, and aryl mesylates with arylboronic acids (Suzuki-type coupling), organozincs (Negishi-type coupling), and Grignards (Kumada-type coupling); 3 and the coupling between polyfunctinal arylzincs and primary alkyl iodides, 4 as well as the coupling of propagylic dithioacetals with Grignard reagents. 5In a previous paper, we described the palladium-catalyzed cross-coupling of 4-tosyl coumarin with acetylenes or zinc reagents. 6 These reactions allow us to generate diversified 4-alkynyl coumarins in good yields under mild conditions. In this letter, we report our recent results of using nickel (0) as a catalyst to couple 4-diethylphosphonooxycoumarin with a variety of organozinc reagents in order to synthesize diversified 4-aryl and alkyl coumarins. Although various methods are known in the literature for the synthesis of 4-substituted coumarin, most of them