TY - JOUR
T1 - Organopalladium compounds with a chiral palladated carbon atom. Facile isolation of optically active cyclopalladated complexes containing the (S)- or (R)-[2-NMe2C6H4CH(SiMe3)] monoanion. Molecular structure of {2-[1-(S)-(dimethylamino)ethyl]phenyl}[2-(dimethylamino)-α- (trimethylsilyl)benzyl]palladium(II)
AU - Maassarani, Fida
AU - Pfeffer, Michel
AU - Le Borgne, Guy
AU - Jastrzebski, Johann T B H
AU - Van Koten, Gerard
PY - 1987
Y1 - 1987
N2 - A series of mixed metallobicyclic compounds of general formula [Pd(N C)(dmat-Si], in which dmat-Si is the monoanionic 2-NMe2C6H4CH(SiMe3) chelate and N C is one of the monoanionic chelates 2-NMe2CH2C6H4 (dmba), 8-C9H6NCH2 (8-mq), or the pure S enantiomer of 2-NMe2CH(Me)C6H4 ((S)-dmba), has been synthesized via the transmetalation reaction of dmat-SiLi (1) with one of the dimers [{Pd-(N C)(μ-Cl)}2]. The 2:1 molar reaction of 1 with [Pd(SEt2)2Cl2] afforded as the main product the C-C coupled compound [dmat-Si]2 (3) and the symmetric product [Pd(dmat-Si)2] (2) in only 4% yield. [Pd-{(S)-dmba}(dmat-Si)] (6) is formed as a mixture of the two diastereomers, arising from the configuration (either R in 6a or S in 6b) of the benzylic carbon atom of the dmat-Si chelate. These diastereomers can be separated by fractional crystallization. The molecular structure of the most accessible diastereomer 6b has been determined by an X-ray diffraction study: C22H34N2PdSi, monoclinic, P21, a = 10.027 (2) Å, b = 11.481 (4) Å, c = 10.833 (2) Å, β = 115.08 (2)°, V = 1129.5 Å3, Z = 2 for 1843 (I > σ(I)) reflections, μ(Mo Kα) = 8.7 cm-1, R = 0.0200, Rw = 0.0289. The square-planar configuration about the Pd atom contains the C N chelates in the cis arrangement while the absolute configuration of the benzylic carbon atom bearing the SiMe3 group is S. Reactions of [Pd(N C)(dmat-Si)] with either methyl vinyl ketone or acetyl chloride did not afford functionalized dmat-Si ligands via the cross-coupling reaction. Instead reaction of [Pd-(dmba)(dmat-Si)] (4) with PhCH2Br yielded the ammonium salt of the cross-coupled product [2-{(PhCH2)NMe2CH2}C6H 4CH2Ph]+Br- together with [{Pd(dmat-Si)(μ-Br)}2] (7). The latter compound is a mixture of cis and trans isomers and gives the monomer [Pd(dmat-Si)PyBr] (8) on reaction with pyridine.
AB - A series of mixed metallobicyclic compounds of general formula [Pd(N C)(dmat-Si], in which dmat-Si is the monoanionic 2-NMe2C6H4CH(SiMe3) chelate and N C is one of the monoanionic chelates 2-NMe2CH2C6H4 (dmba), 8-C9H6NCH2 (8-mq), or the pure S enantiomer of 2-NMe2CH(Me)C6H4 ((S)-dmba), has been synthesized via the transmetalation reaction of dmat-SiLi (1) with one of the dimers [{Pd-(N C)(μ-Cl)}2]. The 2:1 molar reaction of 1 with [Pd(SEt2)2Cl2] afforded as the main product the C-C coupled compound [dmat-Si]2 (3) and the symmetric product [Pd(dmat-Si)2] (2) in only 4% yield. [Pd-{(S)-dmba}(dmat-Si)] (6) is formed as a mixture of the two diastereomers, arising from the configuration (either R in 6a or S in 6b) of the benzylic carbon atom of the dmat-Si chelate. These diastereomers can be separated by fractional crystallization. The molecular structure of the most accessible diastereomer 6b has been determined by an X-ray diffraction study: C22H34N2PdSi, monoclinic, P21, a = 10.027 (2) Å, b = 11.481 (4) Å, c = 10.833 (2) Å, β = 115.08 (2)°, V = 1129.5 Å3, Z = 2 for 1843 (I > σ(I)) reflections, μ(Mo Kα) = 8.7 cm-1, R = 0.0200, Rw = 0.0289. The square-planar configuration about the Pd atom contains the C N chelates in the cis arrangement while the absolute configuration of the benzylic carbon atom bearing the SiMe3 group is S. Reactions of [Pd(N C)(dmat-Si)] with either methyl vinyl ketone or acetyl chloride did not afford functionalized dmat-Si ligands via the cross-coupling reaction. Instead reaction of [Pd-(dmba)(dmat-Si)] (4) with PhCH2Br yielded the ammonium salt of the cross-coupled product [2-{(PhCH2)NMe2CH2}C6H 4CH2Ph]+Br- together with [{Pd(dmat-Si)(μ-Br)}2] (7). The latter compound is a mixture of cis and trans isomers and gives the monomer [Pd(dmat-Si)PyBr] (8) on reaction with pyridine.
UR - http://www.scopus.com/inward/record.url?scp=0001032893&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0001032893
SN - 0276-7333
VL - 6
SP - 1111
EP - 1118
JO - Organometallics
JF - Organometallics
IS - 5
ER -