Palladium-Catalyzed Cross Coupling of Secondary and Tertiary Alkyl Bromides with a Nitrogen Nucleophile.
Palladium-Catalyzed Cross Coupling of Secondary and Tertiary Alkyl Bromides with a Nitrogen Nucleophile.
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DOI：
10.1021/acscentsci.6b00187
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发表时间：
2016-09-28
影响因子：
18.2
通讯作者：
Hartwig, John F.
中科院分区：
文献类型：
--
作者：
Peacock, D. Matthew;Roos, Casey B.;Hartwig, John F.
我们报道了一类新的催化反应：用氮亲核试剂热取代仲烷基卤化物和或叔烷基卤化物。氮亲核试剂与烷基卤化物的烷基化是构建C-N键的经典方法，但由于相互竞争的消除反应，传统的取代反应难以与仲烷基或叔烷基亲电试剂实现。催化过程可以解决这一限制，但烷基卤化物与氮亲核试剂的热催化偶联以及未活化的叔烷基卤化物与氮亲核试剂的任何类型的催化偶联都是未知的。我们报道了未活化的仲烷基溴和叔烷基溴与二苯甲酮亚胺的偶联，在钯的存在下，通过受阻的三烷基膦Cy2t-BuP连接产生受保护的伯胺。机理研究表明，烷基卤化物的胺化是通过可逆反应形成游离烷基自由基而发生的。钯配合物通过可逆生成烷基自由基，催化烷基卤化物生成含仲烷基和叔烷基的受保护伯胺。
We report a new class of catalytic reaction: the thermal substitution of a secondary and or tertiary alkyl halide with a nitrogen nucleophile. The alkylation of a nitrogen nucleophile with an alkyl halide is a classical method for the construction of C–N bonds, but traditional substitution reactions are challenging to achieve with a secondary and or tertiary alkyl electrophile due to competing elimination reactions. A catalytic process could address this limitation, but thermal, catalytic coupling of alkyl halides with a nitrogen nucleophile and any type of catalytic coupling of an unactivated tertiary alkyl halide with a nitrogen nucleophile are unknown. We report the coupling of unactivated secondary and tertiary alkyl bromides with benzophenone imines to produce protected primary amines in the presence of palladium ligated by the hindered trialkylphosphine Cy2t-BuP. Mechanistic studies indicate that this amination of alkyl halides occurs by a reversible reaction to form a free alkyl radical. Palladium complexes catalyze the reaction of alkyl halides to form protected primary amines bearing secondary and tertiary alkyl groups by reversible generation of an alkyl radical.
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影响因子：
15
作者：
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通讯作者：
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影响因子：
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