Resolutions of tertiary phosphines and arsines with orthometallated palladium (II)—amine complexes

Wild, S. Bruce

doi:10.1016/s0010-8545(97)00046-5

Cited by 211 publications

(122 citation statements)

References 63 publications

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“…This property of palladacycles is to a large extent responsible for their efficiency in chiral recognition. 53 To estimate the influence of the chlorine atom at po sition 3 of the phenylene fragment on the conformation of the palladacycle, we performed repeated 1 H NMR spec troscopic study of PPh 3 adduct 5. 54,55 A comparison of the spectroscopic characteristics of phosphine complex 4 and its analog 5 shows that the new palladacycle exists * Hereinafter, the conformational analysis of racemic complexes was performed for the (S) enantiomer.…”

Section: Methodsmentioning

confidence: 99%

A new method for modification of CN-palladacycles

et al. 2005

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The reaction of benzylaminate CN palladacycle with chlorine dioxide was found to pro duce the 3 chlorine substituted analog through the formal insertion of chlorine into the Pd-C bond followed by repeated ortho palladation of the modified ligand. The structure of the resulting dimeric complex was confirmed by X ray diffraction study of its triphenylphosphine derivative. A comparison of the 1 H NMR spectra of the phosphine adducts of the starting and chlorinated complexes shows high conformational stability of the new palladacycle. Advan tages of the new route to conformational stabilization of labile palladacycles are discussed.

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Section: Methodsmentioning

confidence: 99%

A new method for modification of CN-palladacycles

et al. 2005

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“…The cleavage reaction of the chlorido-bridged dimer bis[μ-Cl(S)-2-{1-(dimethylamino)ethyl}phenyl-C,N-palladium(II)] 61 with an excess of 2,2-dimethylaziridine (a) in CH 2 Cl 2 affords the square planar palladium(II) complex Cl(C 6 H 4 CHCH 3 NMe 2 -C,N)-(NHCH 2 CMe 2 )Pd (1a) (Scheme 1). Light yellow 1a is obtained with 50% yield, and is air-stable, soluble in polar solvents (CH 2 Cl 2 ), but insoluble in non-polar solvents (n-pentane).…”

Section: Resultsmentioning

confidence: 99%

Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(ii) and palladium(ii)

et al. 2012

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“…The only attempt to perform asymmetric CLE has been unsuccessful. 17 High efficiency of cyclopalladated complexes in optical resolution 18, 19 and enantioselective catalysis, 20-23 as reagents for the enantiomeric purity determination, 24,25 and as matrices for asymmetric synthesis 26-28 was documented. This stimulated the estimation of their potential as chirality inductors in CLE reactions.…”

Section: Methodsmentioning

confidence: 99%

Asymmetric exchange of cyclopalladated ligands: A new route to optically active phosphapalladacycles

et al. 2006

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An asymmetric version of the cyclopalladated ligand exchange reaction was developed. This procedure involves the use of prochiral phosphines in an aprotic medium. A benzylaminate palladacycle bearing the primary amino group and the bulky Bu t substituent at the C* stereo center serves as a chirality inductor.Key words: asymmetric induction, C-H bond activation, cyclopalladated ligand exchange, optically active phospha and azapalladacycles, X ray diffraction analysis.Although the idea of asymmetric C-H bond activa tion by transition metals is attractive, examples of this process are scarce. In a special case of cyclopalladation, two versions of asymmetric C-H bond activation under control of either external sources of chirality (bases) 1-7 or inner sphere sources are known. Bidentate N,N 8,9 and P,P donor 10,11 ligands were tested as the latter sources. The chirality transfer from chelated ligands proved to be highly efficient in the closure of C*O 9 and C*C palladacycles (see Refs 8, 10, and 11), whereas an attempt to generate planar chirality upon the formation of a CN palladacycle with the use of an optically active monodentate S* donor ligand (sulfoxide) in a metallating agent failed. 12 Chelation of phosphino P ylides giving rise to PC* palladacycles with diastereoselectivity of ~70% de (see Refs 13 and 14) is the only example of the use of CN palladacycles as chirality inductors. However, con figurational lability of such systems substantially limits their use.The aim of the present study was to develop a new method of asymmetric C-H bond activation based on cyclopalladated ligand exchange (CLE ) 15,16 (Scheme 1). Scheme 1Although the starting palladacycle in the CLE reac tion can serve not only as the metallating agent but also as the source of chirality, only achiral versions of this reac tion have been examined. The only attempt to perform asymmetric CLE has been unsuccessful. 17 High efficiency of cyclopalladated complexes in optical resolution 18,19 and enantioselective catalysis, 20-23 as reagents for the enantiomeric purity determination, 24,25 and as matrices for asymmetric synthesis 26-28 was documented. This stimulated the estimation of their potential as chirality inductors in CLE reactions. The preliminary results of our investigations in this field have been published re cently. 29 Results and DiscussionWe chose a series of benzylaminate CN dimers (1a,b and 2a-7a), which differ in the nature of the amino The asymmetric atom directly bound to the metal atom is marked with an asterisk.The more laconic term transcyclometallation has been pro posed 16 for the description of such reactions; however, this term does not reflects the essence of the process, in which ligands rather than metal atoms (transmetallation) are exchanged.The number of the complex corresponds to the superscript n in the code of the starting ligand HL n , and the letters stand for different derivatives of this palladacycle.

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Resolutions of tertiary phosphines and arsines with orthometallated palladium (II)—amine complexes

Cited by 211 publications

References 63 publications

A new method for modification of CN-palladacycles

A new method for modification of CN-palladacycles

Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(ii) and palladium(ii)

Asymmetric exchange of cyclopalladated ligands: A new route to optically active phosphapalladacycles

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