122889-47-8Relevant academic research and scientific papers
Palladium(II)-allyl complexes containing chiral N-donor ferrocenyl ligands
Platero-Prats, Ana E.,Pérez, Sonia,López, Concepción,Solans, Xavier,Font-Bardía, Mercè,van Leeuwen, Piet W.N.M.,van Strijdonck, Gino P.F.,Freixa, Zoraida
, p. 4215 - 4226 (2007)
A study of the reactivity of enantiopure ferrocenylimine (SC)-[FcCH{double bond, long}N-CH(Me)(Ph)] {Fc = (η5-C5H5)Fe{(η5-C 5H4)-} (1a) with palladium(II)-allyl complexes [Pd(η3-1R1,3R2-C3H3 )(μ-Cl)]2 {R1 = H and R2 = H (2), Ph (3) or R1 = R2 = Ph (4)} is reported. Treatment of 1a with 2 or 3 {in a molar ratio Pd(II):1a = 1} in CH2Cl2 at 298 K produced [Pd(η3-3R2-C3H4){FcCH{do uble bond, long}N-CH(Me)(Ph)}Cl] {R2 = H (5a) or Ph (6a)}. When the reaction was carried out under identical experimental conditions using complex 4 as starting material no evidence for the formation of [Pd(η3-1,3-Ph2-C3H3){FcC H{double bond, long}N-CH(Me)(Ph)}Cl] (7a) was found. Additional studies on the reactivity of (SC)-[FcCH{double bond, long}N-CH(R3)(CH2OH)] {R3 = Me (1b) or CHMe2 (1c)} with complex 4 showed the importance of the bulk of the substituents on the palladium(II) allyl-complex (2-4) or on the ferrocenylimines (1) in this type of reaction. The crystal structure of 5a showed that: (a) the ferrocenylimine adopts an anti-(E) conformation and behaves as an N-donor ligand, (b) the chloride is in acis-arrangement to the nitrogen and (c) the allyl group binds to the palladium(II) in a η3-fashion. Solution NMR studies of 5a and 6a and [Pd(η3-1,3-Ph2-C3H3){FcC H{double bond, long}N-CH(Me)(CH2OH)}Cl] (7b) revealed the coexistence of several isomers in solution. The stoichiometric reaction between 6a and sodium diethyl 2-methylmalonate reveals that the formation of the achiral linear trans-(E) isomer of Ph-CH{double bond, long}CH-CH2Nu (8) was preferred over the branched derivative (9). A comparative study of the potential utility of ligand 1a, complex 5a and the amine (SC)-H2N-CH(Me)(Ph) (11) as catalysts in the allylic alkylation of (E)-3-phenyl-2-propenyl (cinnamyl) acetate with the nucleophile diethyl 2-methylmalonate (Nu-) is reported.
