Development of a new class of chiral phosphorus ligands: P-chirogenic diaminophosphine oxides. A unique source of enantioselection in Pd-catalyzed asymmetric construction of quaternary carbons.
Development of a new class of chiral phosphorus ligands: P-chirogenic diaminophosphine oxides. A unique source of enantioselection in Pd-catalyzed asymmetric construction of quaternary carbons.
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DOI：
10.1021/jo050800y
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发表时间：
2005-07
期刊：
影响因子：
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通讯作者：
T. Nemoto;Takamasa Masuda;Takayoshi Matsumoto;Y. Hamada
中科院分区：
文献类型：
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作者：
T. Nemoto;Takamasa Masuda;Takayoshi Matsumoto;Y. Hamada
我们最近开发了一类新的手性磷配体：p -致氮二氨基膦氧化物。这些五价磷化合物已成功地应用于钯催化的叔碳和季碳的不对称结构。实际配体结构为三价磷17，由bsa诱导前配体6的P(V)向P（III）转化原位生成。详细的机理研究，包括不对称放大和初始速率动力学，表明配合物18 [Pd-17（1:2）配合物]是活性催化剂。阐明了配体侧臂上氮原子的重要作用。不对称季碳结构中对映体选择的来源是由N-Zn配位介导的二次配体与底物相互作用。
[reaction: see text] We have recently developed a new class of chiral phosphorus ligands: P-chirogenic diaminophosphine oxides. These pentavalent phosphorus compounds have been successfully applied to Pd-catalyzed asymmetric construction of tertiary and quaternary carbons. The actual ligand structure was the trivalent phosphorus species 17, which was generated in situ by BSA-induced P(V) to P(III) transformation of 6, the preligand. Detailed mechanistic studies, including asymmetric amplification and initial rate kinetics, revealed that complex 18 [Pd-17 (1:2) complex] was the active catalyst. The important function of the nitrogen atom on the sidearm in the ligands was also clarified. The source of enantioselection in the construction of asymmetric quaternary carbons was the secondary ligand substrate interaction mediated by N-Zn coordination.