J. Magali Cadena

Optically active palladacycles containing imines derived from 1-(1-naphthyl)ethylamine: new resolving agents for P-chiral phosphines

Abstract The synthesis of the new palladium metallacycles containing imines derived from 1-(1-naphthyl)ethylamine is reported. These new organometallic complexes have been used to resolve the P-chiral ligand benzylcyclohexylphenylphosphine. The absolute configuration of ( R C , S P )-[PdCl{2-[HCN-CH(Me)C 10 H 6 ]-3-ClC 6 H 3 }(PBzCyPh)] has been determined by single crystal X-ray analysis.

Synthesis and resolution of benzylisopropylphenylphosphine, a monodentate P-chiral ligand

Abstract The synthesis of benzylisopropylphenylphosphine by reaction between the benzylphenylphosphide anion and isopropyl chloride and its subsequent resolution by means of an optically active palladium metallacycle is reported. The synthesis of the organometallic complex [Pd(η 3 -2-MeC 3 H 4 )Cl(PBn i PrPh)] is also described, as well as the assignment of the absolute configuration of the coordinated phosphine by mono- and bidimensional proton NMR spectra, using the homochiral palladacycle as a reference point. In order to estimate the height of the energy barrier corresponding to the rotation of the phosphine ligand around the PdP bond, several calculations were performed at the semiempirical PM3(tm) level.

Optically active cyclopalladated compounds containing P-chiral ligands. Restricted rotation around the PdP bond

The synthesis of the optically active complexes [PdCl(C10H6CHMeNMe2)L] (L=PPh3, PBn2Ph, PHBnPh and PBnCyPh) and the resolution of the secondary phosphine PHBnPh is reported. The study of the NMR data of these mononuclear compounds shows that in some of these complexes the rotation around the PdP bond is restricted. A relationship between the δ values of the aromatic proton adjacent to the PdC bond and the conformation of the Pd–phosphine fragment can be found and NMR data permit the assignment of the absolute configuration of the phosphine in [PdCl(C10H6CHMeNMe2)(PBnCyPh)]. Several molecular mechanics geometry optimizations were performed using the MMFF94 force field to estimate the height of the energy barrier corresponding to the rotation of the phosphine ligands around the PdP bond. These calculations show the rotation around the PdP bond to be restricted, if the phosphine contains at least one benzylic group, and agree with the results obtained in solution by means of mono- and bi-dimensional NMR.

Synthesis and resolution of a new P-chiral hydroxy phosphine

Abstract The synthesis of the functionalized P-chiral phosphine BzPhP{CH(OH)Ph}and its resolution by palladium metallacycles is reported. The cyclopalladated compound containing the primary amine 1-(1-naphthyl)ethylamine has been shown to be a better resolving agent for this phosphine than the corresponding metallacycle containing the tertiary amine N,N-dimethyl-1-(1-naphthyl)ethylamine

Resolution of Secondary Phosphanes Chiral at Phosphorus by Means of Palladium Metallacycles

The synthesis of new epimeric compounds [PdCl(C−N){(±)-PHPhR}] (C−N = (R)-C10H6CHMeNH2 and (R)-C6H4CHMeNH2, R = Me and PhCH2) containing chiral secondary phosphanes is reported. Some of these diastereomers can be separated by column chromatography; subsequent reaction of these complexes with 1,2-bis(diphenylphosphanyl)ethane (dppe) affords the free phosphanes PHBzPh and PHMePh. The configurational stability of the secondary phosphanes resolved has also been studied.

The first NH aldimine organometallic compound. Isolation and crystal structure

The first NH aldimine organometallic derivative is unexpectedly formed by the cleavage of the nitrogen-carbon bond of the amino acid fragment of the Schiff base 2,4,6-Me3C6H2CH=NCH(CH2Ph)COOEt when the imine is treated with palladium acetate.