LARGE RATE ACCELERATIONS IN THE STILLE REACTION WITH TRI-2-FURYLPHOSPHINE AND TRIPHENYLARSINE AS PALLADIUM LIGANDS - MECHANISTIC AND SYNTHETIC IMPLICATIONS
LARGE RATE ACCELERATIONS IN THE STILLE REACTION WITH TRI-2-FURYLPHOSPHINE AND TRIPHENYLARSINE AS PALLADIUM LIGANDS - MECHANISTIC AND SYNTHETIC IMPLICATIONS
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DOI：
10.1021/ja00025a025
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发表时间：
1991-12-04
影响因子：
15
通讯作者：
KRISHNAN, B
中科院分区：
文献类型：
--
作者：
FARINA, V;KRISHNAN, B
研究了不同钯配体对典型Stille偶联反应速率的影响。使用三-2-呋喃基膦（TFP）和三苯基胂观察到大的速率增强（通常比基于三苯基膦的催化剂高10（2）-10（3）），其被推荐作为烯烃锡烷和亲电子试剂之间的钯催化偶联的新的选择配体。在所提出的证据的基础上，transmetalation，这是催化循环中的速率决定步骤，被假定为涉及金属和锡烷双键之间的π-络合物。通常，容易从Pd（II）解离并允许容易形成该π-络合物的配体是产生最快偶联速率的配体。新的配体的效用证明了几个合成的例子。
The effect of changing the palladium ligands on the rates of typical Stille cross-coupling reactions was studied. Large rate enhancements (typically 10(2)-10(3) over triphenylphosphine-based catalysts) were observed with tri-2-furylphosphine (TFP) and triphenylarsine, which are recommended as the new ligands of choice in the palladium-catalyzed coupling between olefinic stannanes and electrophiles. On the basis of the evidence presented, the transmetalation, which is the rate-determining step in the catalytic cycle, is postulated to involve a pi-complex between the metal and the stannane double bond. In general, ligands that readily dissociate from Pd(II) and allow ready formation of this pi-complex are the ones that produce the fastest coupling rates. The utility of the new ligands is demonstrated with several synthetic examples.