Aerobic Linear Allylic C-H Amination: Overcoming Benzoquinone Inhibition.
Aerobic Linear Allylic C-H Amination: Overcoming Benzoquinone Inhibition.
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DOI：
10.1021/jacs.5b11294
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发表时间：
2016-02-03
影响因子：
15
通讯作者：
White MC
中科院分区：
文献类型：
--
作者：
Pattillo CC;Strambeanu II;Calleja P;Vermeulen NA;Mizuno T;White MC
报道了在Pd(II)/双亚砜/Brønsted碱催化下高效的线性烯丙基C-H胺化反应（LAA）。该反应在制备、操作简单的条件下进行（1等量烯烃，1atm）。O2或空气)，减少Pd(II)/双亚砜催化剂负载，同时提供比使用化学计量苯醌（BQ）作为末端氧化剂的系统更高的周转率和产品收率。钯(II)/苯醌π-酸性相互作用在各种催化过程中被调用，通常被认为有利于促进还原官能化。然而，当不需要这种亲电活化来实现功能化时，高浓度的苯醌可能会与关键的配体（双亚砜）结合竞争并抑制催化作用。动力学研究表明，反应速率与BQ浓度呈反比关系，表明苯醌作为Pd（II）的配体，对催化产生抑制作用。
An efficient aerobic linear allylic C—H amination reaction (LAA) is reported under Pd(II)/bis-sulfoxide/Brønsted base catalysis. The reaction operates under preparative, operationally simple conditions (1 equiv. olefin, 1 atm. O2 or air), with reduced Pd(II)/bis-sulfoxide catalyst loadings while providing higher turnovers and product yields than systems employing stoichiometric benzoquinone (BQ) as the terminal oxidant. Palladium(II)/benzoquinone π-acidic interactions have been invoked in various catalytic processes and are often considered beneficial in promoting reductive functionalizations. When such electrophilic activation for functionalization is not needed, however, benzoquinone at high concentrations may compete with crucial ligand (bis-sulfoxide) binding and inhibit catalysis. Kinetic studies reveal an inverse relationship between the reaction rate and the concentration of BQ, suggesting that benzoquinone is acting as a ligand for Pd(II) which results in an inhibitory effect on catalysis.