Polystyrene-Supported Acyclic Diaminocarbene Palladium Complexes in Sonogashira Cross-Coupling: Stability vs. Catalytic Activity

Catalysts

Vladimir N. Mikhaylov¹  Denis Martin Liakhov¹  Irina A. Balova¹  Viktor N. Sorokoumov¹  Alexander G. Tskhovrebov¹ 

[1] Institute of Chemistry, St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia;

关键词: palladium;    cross-coupling;    Sonogashira coupling;    carbene;    polystyrene;    catalyst activation;    boomerang mechanism;    carbodiimide;    isocyanide;   

DOI  :  10.3390/catal8040141

来源: DOAJ

【 摘 要 】

Two types of immobilized on the amino-functionalized polystyrene-supported acyclic diaminocarbene palladium complexes (ADC-PdII) are investigated under Sonogashira cross-coupling conditions. Depending on substituents in the diaminocarbene fragment immobilized ADC-PdII, systems are found to have different catalytic activity and stability regarding Pd-leaching. PdII-diaminocarbenes possessing protons at both nitrogen atoms smoothly decompose into Pd0-containing species providing a catalytic “cocktail system” with high activity and ability to reuse within nine runs. Polymer-supported palladium (II) complex bearing NBn–Ccarbene–NH-moiety exhibits greater stability while noticeably lower activity under Sonogashira cross-coupling. Four molecular ADC-PdII complexes are also synthesized and investigated with the aim of confirming proposed base-promoted pathway of ADC-PdII conversion through carbodiimide into an active Pd0 forms.

【 授权许可】

Unknown