Rhodium phosphine-π-arene intermediates in the hydroamination of alkenes.
Rhodium phosphine-π-arene intermediates in the hydroamination of alkenes.
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DOI：
10.1021/ja1057949
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发表时间：
2011-03-02
影响因子：
15
通讯作者：
Hartwig JF
中科院分区：
文献类型：
--
作者：
Liu Z;Yamamichi H;Madrahimov ST;Hartwig JF
报道了联芳基二烷基膦铑配合物催化的烯烃与胺分子内氢胺化的详细机理研究。该活性催化剂含有以 κ1、η6 形式结合的膦配体，其中芳烃与铑以 π 键结合。氘代胺与内烯烃的加成表明，该反应是通过 N-H 键跨 C=C 键的反式加成而发生的，并且这种立体化学意味着该反应是通过胺对配位烯烃的亲核攻击而发生的。事实上，阳离子铑片段通过仲胺与烯烃结合，并且烯烃络合物显示为催化剂静止状态。当烯烃浓度较高时，反应在底物中为零级反应，并观察到初级同位素效应。主要同位素效应与对静止状态的烯烃配合物的观察相结合，意味着胺对烯烃的亲核攻击是可逆的，并且随后是限制转换的质子化。该机制构成了铑催化烯烃加成的不寻常途径，并且与钯催化酰胺N-H键与烯烃加成的机制更为密切相关。
A detailed mechanistic study of the intramolecular hydroamination of alkenes with amines catalyzed by rhodium complexes of a biaryldialkylphosphine are reported. The active catalyst is shown to contain the phosphine ligand bound in a κ1, η6 form in which the arene is π-bound to rhodium. Addition of deuterated amine to an internal olefin showed that the reaction occurs by trans addition of the N-H bond across the C=C bond, and this stereochemistry implies that the reaction occurs by nucleophilic attack of the amine on a coordinated alkene. Indeed, the cationic rhodium fragment binds the alkene over the secondary amine, and the olefin complex was shown to be the catalyst resting state. The reaction was zero-order in substrate, when the concentration of olefin was high, and a primary isotope effect was observed. The primary isotope effect, in combination with the observation of the alkene complex as the resting state, implies that nucleophilic attack of the amine on the alkene is reversible and is followed by turnover-limiting protonation. This mechanism constitutes an unusual pathway for rhodium-catalyzed additions to alkenes and is more closely related to the mechanism for palladium-catalyzed addition of amide N-H bonds to alkenes.
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影响因子：
15
作者：
CASALNUOVO, AL;CALABRESE, JC;MILSTEIN, D
通讯作者：
MILSTEIN, D
影响因子：
1.8
作者：
Hartwig, JF
通讯作者：
Hartwig, JF
影响因子：
2.8
作者：
Hauger, BE;Huffman, JC;Caulton, KG
通讯作者：
Caulton, KG
影响因子：
15
作者：
Bender, CF;Widenhoefer, RA
通讯作者：
Widenhoefer, RA
影响因子：
1.1
作者：
CHENG, PT;NYBURG, SC
通讯作者：
NYBURG, SC