Synthesis of trifluoromethyl ketones by palladium-catalyzed cross-coupling reaction of phenyl trifluoroacetate with organoboron compounds
Synthesis of trifluoromethyl ketones by palladium-catalyzed cross-coupling reaction of phenyl trifluoroacetate with organoboron compounds
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DOI：
10.1246/bcsj.74.371
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发表时间：
2001-02-01
影响因子：
4
通讯作者：
Yamamoto, A
中科院分区：
文献类型：
--
作者：
Kakino, R;Shimizu, I;Yamamoto, A
三氟乙酸芳基酯与有机硼化合物在钯配合物催化下的交叉偶联反应在温和条件下以中等至优异的产率得到三氟甲基酮。该催化过程是在三氟乙酸苯酯与Pd（0）络合物氧化加成得到（苯氧）（三氟乙酰基）钯（II）络合物及其随后与苯基硼酸反应释放苯基三氟甲基酮的基础研究的基础上设计的。该催化循环由（a）酯的氧化加成得到酰基（芳氧基）钯中间体，（B）随后与芳基硼化合物的金属间化合物转移，和（c）还原消除组成。钯（0）络合物以及在室温下由乙酸钯和3摩尔量的三丁基膦或亚磷酸盐原位制备的催化剂充当方便且有效的催化剂。该方法适用于广泛的苯基硼酸和萘基硼酸，在温和条件下得到各种芳基三氟甲基酮。芳基全氟烷基酮衍生物可以类似地由各种全氟烷烃羧酸苯酯和芳基硼酸以高产率制备。
Cross-coupling reaction of aryl trifluoroacetates with organoboron compounds catalyzed by palladium complexes gives trifluoromethyl ketones in moderate to excellent yields under mild conditions. The catalytic process has been designed on the basis of fundamental studies dealing with oxidative addition of phenyl trifluoroacetate to a Pd(0) complex to give a (phenoxo)(trifluoroacetyl)palladium(II) complex and its subsequent reaction with phenylboronic acid to liberate phenyl trifluoromethyl ketone. The catalytic cycle is proposed to be composed of (a) oxidative addition of the ester to give acyl(aryloxo)palladium intermediate, (b) the subsequent transmetallation with arylboron compounds, and (c) reductive elimination. Palladium(0) complexes, as well as catalysts prepared in situ from palladium acetate and 3 molar amounts of tributylphosphine or phosphite at room temperature, serve as convenient and effective catalysts. The process is applicable to a wide range of phenyl- and naphthylboronic acids to give various aryl trifluoromethyl ketones under mild conditions. Aryl perfluoroalkyl ketone derivatives can be similarly prepared in high yields from various phenyl perfluoroalkanecarboxylates and arylboronic acids.