• Title/Summary/Keyword: Chiral ligand

Search Result 51, Processing Time 0.025 seconds

Chiral [Iminophosphoranyl]ferrocenes: Synthesis, Coordination Chemistry, and Catalytic Application

  • Co, Thanh Thien;Shim, Sang-Chul;Cho, Chan-Sik;Kim, Dong-Uk;Kim, Tae-Jeong
    • Bulletin of the Korean Chemical Society
    • /
    • v.26 no.9
    • /
    • pp.1359-1365
    • /
    • 2005

  • A series of new chiral [iminophosphoranyl]ferrocenes, {${\eta}^5-C_5H_4-(PPh_2=N-2,6-R_2-C_6H_3)$}Fe{${\eta}^5-C_5H_3-1-PPh^2-2-CH(Me)NMe_2$} (1: R = Me, $^iPr$), {${\eta}^5{-C_5H_4-(PPh_2=N-2,6-R_2}^1-C_6H_3)$}Fe{${\eta}^5-C_5H_3-1-(PPh_2=N-2,6-R_2-C_6H_3)-2-CH(Me)R_2$} (2: $R^1\;=\;Me,\;^iPr;\;R^2\;=\;NMe_2$, OMe), and $({\eta}^5-C_5H_5)Fe${${\eta}^5-C_5H_4-1-PR_2-2-CH(Me)N=PPh_3$} (3:R = Ph, $C_6H_{11}$) have been prepared from the reaction of [1,1'-diphenylphosphino-2-(N,N-dimethylamino) ethyl]ferrocene with arylazides (1 & 2) and the reaction of phosphine dichlorides ($R_3PCl_{2}$) with [1,1'-diphenylphosphino-2-aminoethyl]ferrocene (3), respectively. They form palladium complexes of the type $[Pd(C_3H_5)(L)]BF_4$ (4-6: L = 1-3), where the ligand (L) adopts an ${\eta}^2-N,N\;(2)\;or\;{\eta}^2$-P,N (3) as expected. In the case of 1, a potential terdentate, an ${\eta}^2$-P,N mode is realized with the exclusion of the –=NAr group from the coordination sphere. Complexes 4-6 were employed as catalysts for allylic alkylation of 1,3-diphenylallyl acetate leading to an almost stoichiometric product yield with modest enantiomeric excess (up to 74% ee). Rh(I)-complexes incorporating 1-3 were also prepared in situ for allylic alkylation of cinnamyl acetate as a probe for both regio- and enantioselectivities of the reaction. The reaction exhibited high regiocontrol in favor of a linear achiral isomer regardless of the ligand employed.

  • https://doi.org/10.5012/bkcs.2005.26.9.1359 인용 PDF KSCI

Chiral C2-Symmetric α-and ω-Diimines with Bulky Substituents at Nitrogen: Synthesis and Catalytic Properties of Some Copper Complexes

  • Park, Dong-Kyu;Ryu, Eun-Sook;Paek, Seung-Hwan;Shim, Sang-Chul;Cho, Chan-Sik;Kim, Tae-Jeong
    • Bulletin of the Korean Chemical Society
    • /
    • v.23 no.5
    • /
    • pp.721-726
    • /
    • 2002

  • Two new C2-symmetric chiral $\alpha-$ and w-Diimines incorporating bulky ferrocenylethylamine and their copper(I)complexes have been synthesized and characterized by analytical and various spectroscopic techniques. The catalytic activities of these complexes have been tested in the asymmetric cyclopropanation of a series of olefins with some diazoacetates to achieve varying degree of dia- and enantio-selectivities depending on the nature of the ligand, the substrates, and the reagents. Some mechanistic implication has been made with regard to the interactions among all these chemical species.

  • https://doi.org/10.5012/bkcs.2002.23.5.721 인용 PDF KSCI

Enantioselective Reformatsky Reaction Using Cinchona Alkaloids as Chiral Ligands (Cinchona 알칼로이드를 키랄 리간드로 이용한 비대칭 Reformatsky 반응)

  • Park, Doo-Han;Choi, Ho-Jin;Lee, Sang-Gi
    • Journal of the Korean Chemical Society
    • /
    • v.47 no.6
    • /
    • pp.597-600
    • /
    • 2003

  • Cinchona alkaloids (1-4) were used as chiral ligands for the enantioselective Reformatsky reactions. The order of addition of the Reformatsky reagent to ligands was the important factors for the chiral induction. The ratio of Reformatsky reagent to ligand and aldehyde was also effected on the reaction yields.

  • https://doi.org/10.5012/jkcs.2003.47.6.597 인용 PDF KSCI KPUBS HTML