New Chiral P-N Ligands for the Regio- and Stereoselective Pd-Catalyzed Dimerization of Styrene

Molecules

Lidia Fanfoni¹  Angelo Meduri¹  Ennio Zangrando¹  Sergio Castillon¹  Fulvia Felluga¹ 

[1] ¹Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, Via Licio Giorgieri 1, 34127 Trieste, Italy ²Department de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, C. Marcel.lí Domingo s/n 43007 Tarragona, Spain

关键词: hybrid phosphorus-nitrogen ligands;    palladium;    alkene dimerization;   

DOI  :  10.3390/molecules16021804

来源: mdpi

【 摘 要 】

Two new chiral, enantiomerically pure, hybrid P-N ligands, namely (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octan-4-one (1) and (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octane (2), have been synthesized starting from L-proline. The two ligands differ in the presence or not of a carbonyl group in the diazaphosphane ring. Their coordination chemistry towards Pd(II) was studied by reacting them with [Pd(CH₃)Cl(cod)]. A different behaviour was observed: ligand 2 shows the expected bidentate chelating behaviour leading to the mononuclear Pd-complex, while ligand 1 acts as a terdentate ligand giving a dinuclear species. The corresponding cationic derivatives were obtained from the palladium neutral complexes, both as mono- and dinuclear derivatives, and tested as precatalysts for styrene dimerization, yielding E-1,3-diphenyl-1-butene regio- and stereoselectively as the sole product. A detailed analysis of the catalytic behaviour is reported.

【 授权许可】

CC BY   
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.