Efficient cross-coupling of secondary alkyltrifluoroborates with aryl chlorides-reaction discovery using parallel microscale experimentation
Efficient cross-coupling of secondary alkyltrifluoroborates with aryl chlorides-reaction discovery using parallel microscale experimentation
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DOI：
10.1021/ja8031423
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发表时间：
2008-07-23
影响因子：
15
通讯作者：
Molander, Gary A.
中科院分区：
文献类型：
--
作者：
Dreher, Spencer D.;Dormer, Peter G.;Molander, Gary A.
采用微型平行实验发现了三种能够使二级有机三氟硼酸盐与空间位阻和电子效应要求较高的芳基氯化物和溴化物偶联的催化剂体系。随后的结果代表了烷基硼与芳基氯化物偶联的首次全面研究，特别是使用二级烷基硼试剂的情况。在一些受阻底物的交叉偶联中涉及一种依赖配体的β - 氢消除/再插入机制，在某些情况下会导致偶联产物的异构体混合物。
Microscale parallel experimentation was used to discover three catalyst systems capable of coupling secondary organotrifluoroborates with sterically and electronically demanding aryl chlorides and bromides. The ensuing results represent the first comprehensive study of alkylboron coupling to aryl chlorides and, in particular, using secondary alkylboron partners. A ligand-dependent beta-hydride elimination/reinsertion mechanism was implicated in the cross-coupling of more hindered substrates, leading to isomeric mixtures of coupled products in some cases.