128951-70-2Relevant academic research and scientific papers
Comparative studies on reactions of α,β- and β,γ-unsaturated amides and acids with nickel(0), palladium(0), and platinum(0) complexes. Preparation of new five- and six-membered nickel- and palladium-containing cyclic amide and ester complexes
Yamamoto, Takakazu,Sano, Kenji,Osakada, Kohtaro,Komiya, Sanshiro,Yamamoto, Akio,Kushi, Yoshihiko,Tada, Toshiji
, p. 2396 - 2403 (2008/10/08)
Reactivities of α,β- and β,γ-unsaturated amides as well as acids with zerovalent nickel, palladium, and platinum complexes have been compared. α,β-Unsaturated amides and acids form nickel-containing five-membered cyclic amide and ester complexes, (PR3)NiCH2CH(CH3)CONH (PR3 = PCy3, PEt3, P(t-Bu)2Et, dppe, dppp, dppb) and (PCy3)NiCH2CH(CH3)COO. β,γ-Unsaturated amides and acids afford nickel-containing six-membered cyclic amide and ester complexes, (PCy3)NiCH2CH2CH2CONH and (PCy3)NiCH2CH2CH2COO, whereas the palladium-containing six-membered cyclic ester complex (PCy3)PdCH2CH2CH2COO has been obtained from Pd(PCy3)2 and 3-butenoic acid. Pt(cod)2 in the presence of PCy3 reacted with methacrylamides to give olefin-coordinated Pt(0) complexes, Pt(PCy3)(CH2=C(CH3)CONHR)2 (R = H, Ph), whereas the reaction with α,β- and β,γ-unsaturated acids gave oxidative-addition products of the acids, trans-PtH(O2CR)(PCy3)2 (R = -C(CH3)=CH2, -CH2CH=CH2). An X-ray crystallographic analysis of one of the five-membered nickel-containing cyclic amides [(PEt3)NiCH2CH(CH3)CONH]4, was carried out. A novel tetrameric cyclic structure containing a nickelacyclic amide framework linked through Ni-O bonds with adjacent amide carbonyl groups has been established. Treatment of the nickel- and palladium-containing five- and six-membered cyclic amide and ester complexes with CO liberated cyclic imides and anhydrides. Thermolysis and reactions of the nickelacyclic complexes with AlCl3 and maleic anhydride led to β-elimination reactions with release of unsaturated amides and acids.
