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首页> 外文期刊>Heterocycles: An International Journal for Reviews and Communications in Heterocyclic Chemistry >PALLADIUM-CATALYZED CROSS-COUPLING REACTION OF HETEROARYLTRIOLBORATES WITH ARYL HALIDES FOR SYNTHESIS OF BIARYLS
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PALLADIUM-CATALYZED CROSS-COUPLING REACTION OF HETEROARYLTRIOLBORATES WITH ARYL HALIDES FOR SYNTHESIS OF BIARYLS

机译:杂芳基硼酸酯与芳基卤化物的钯催化交叉偶联反应用于合成双芳基

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Cyclic triolborates possessing a heteroaromatic ring on the boron atom [ArB(OCH2)3CHCH3]M (M=K, Na, Li) were prepared in high yields from heteroarylboronic acids, 1,1,1-tris(hydroxymethyl)ethane (triol) and KOH or NaH. The corresponding lithium salts were synthesized from aryllithiums, B(OMe)3 and triol. They were air-stable white solids that were convenient for handling in air. High performance of these triolborates for metal-catalyzed bond-forming reactions was demonstrated in palladium-catalyzed cross-coupling reactions with haloarenes. Although the use of heteroarylboronic acids often results in very low yields due to competitive hydrolytic B-C bond cleavage with water under typical conditions using aqueous bases, triolborates possessing a 2-pyridyl, 3-pyridyl or 2-thiophenyl ring afforded biaryls in high yields at 50-120 °C in anhydrous DMF. There was a strong accelerating effect of CuI for reactions of 2- and 3-pyridylborate derivatives, whereas 2-thiophenyl derivatives reacted smoothly resulting in high yields in the absence of CuI.
机译:从杂芳基硼酸1,1,1-三(羟甲基)乙烷(三醇)高收率制备硼原子[ArB(OCH2)3CHCH3] M(M = K,Na,Li)上具有杂芳环的环状三硼酸酯和KOH或NaH。由芳基锂,B(OMe)3和三醇合成相应的锂盐。它们是空气稳定的白色固体,很容易在空气中处理。这些三硼硼酸盐在金属催化的与卤代芳烃的交叉偶联反应中表现出对金属催化的键形成反应的高性能。尽管使用杂芳基硼酸通常会由于在典型条件下使用水性碱在水中进行竞争性水解BC键裂解而导致非常低的收率,但拥有2-吡啶基,3-吡啶基或2-硫代苯环的三硼酸酯在50的情况下提供了高收率的联芳基-120°C在无水DMF中。 CuI对2-和3-吡啶基硼酸酯衍生物的反应具有很强的促进作用,而2-thiophenyl衍生物在没有CuI的情况下反应平稳,导致高收率。

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