Synthesis and Structure of New [3]Silametallocenophanes of Group 8 Metals

Braunschweig, Holger; Damme, Alexander; Hammond, Kai; Mager, Julian

doi:10.1021/om300564y

Cited by 5 publications

(4 citation statements)

References 46 publications

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“…For the development of a diastereoselective version of this reaction type, we have prepared the ruthenocene bisimidazoline ligand RuBI (Scheme ). The short ligand synthesis works in close analogy to the one of the corresponding ferrocene ligand. , Dilithiation of ruthenocene and trapping of the resulting biscarbanion with N , N -dimethylthiocarbamoyl chloride provided bisthioamide 1 . The latter was activated by triethyloxonium tetrafluoroborate for the bisimidazoline formation by treatment with the chiral diamine ( R , R )-1,2-diamino-1,2-diphenylethane (( R , R )-DADPE).…”

Section: Resultsmentioning

confidence: 99%

Cooperative Bimetallic Asymmetric Catalysis: Comparison of a Planar Chiral Ruthenocene Bis-Palladacycle to the Corresponding Ferrocene

et al. 2014

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Cooperative asymmetric catalysts often offer advantages in terms of activity, stereoselectivity, and generality as compared to more traditional single point activation catalysts. In cooperative bimetallic catalysis, the intermetallic distance is a crucial parameter for the outcome of a reaction and an optimal synergy of both metal centers. We have recently developed a number of catalytic asymmetric reactions, which are efficiently catalyzed by a planar chiral ferrocene based bispalladacycle and for which the cooperativity of two Pd centers has already been demonstrated. To get more insight into the role of the Pd/Pd distance in such metallocene bismetallacycles, in the present study a corresponding ruthenocene based Pd2-complex has been prepared by the first direct diastereoselective biscyclopalladation of a chiral ruthenocene ligand. In addition, the first highly diastereoselective direct monocyclopalladation of a homochiral ruthenocene is reported. The effect of the increased Cp/Cp distance within the ruthenocene bispalladacycle has been examined in four catalytic asymmetric applications: the aza-Claisen rearrangement of Z-configured allylic N-aryltrifluoroacetimidates, the direct 1,4-addition of α-cyanoacetates to enones, a tandem azlactone formation/1,4-addition to enones and a tandem reaction to form quaternary α-aminosuccinimides by in situ azlactone formation, 1,4-addition to a nitroolefin, and a Nef-type nitro-to-carbonyl transformation as key steps. For each reaction studied, it was found that with some substrates the ferrocene based catalyst is superior, whereas for other substrates the ruthenocene backbone is more favorable. The ruthenocene based bispalladacycle can thus be considered to be a useful and complementary alternative for cooperative bimetallic catalysis.

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Section: Resultsmentioning

confidence: 99%

Cooperative Bimetallic Asymmetric Catalysis: Comparison of a Planar Chiral Ruthenocene Bis-Palladacycle to the Corresponding Ferrocene

et al. 2014

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“…With an elongated silane chain, trisilane bridged complex 61b adopted a nonstrained conformation. 105 The center transition metals and the Si number of the silane chain play signicant roles in controlling the ring strain, which is a key factor affecting the reactivity and cleavage of the Si-C(ipso carbon) bond. Regarding compound 59, where an iron center is present with a d 6 conguration, all the occupied molecular orbitals mainly composed of d orbitals exhibit binding properties.…”

Section: Macrocyclic Compounds Incorporated With a Disilane Bridgementioning

confidence: 99%

“…With an elongated silane chain, trisilane bridged complex 61b adopted a nonstrained conformation. 105 …”

Section: Disilane-bridged Chromophoresmentioning

confidence: 99%

Disilane-bridged architectures: an emerging class of molecular materials

Zhou,

Gai,

et al. 2023

Chem. Sci.

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“…From the 3d metals, strained metalloarenophanes have been synthesized for Ti, V, Cr, Mn, Fe, Co, and Ni . However, higher homologues of the 4d row have only been reported for groups 6 (Mo) and 8 (Ru). Even more scarce are 5d metalloarenophanes, which are known solely for osmium. , Although many different homoatomic bridges are known for the 3d metals and ruthenium, osmocenophanes feature exclusively three-atom bridges (e.g., trithia- and trisila- moieties) and not smaller bridges with only one or two atoms.…”

Section: Introductionmentioning

confidence: 99%

Structure and Reactivity of Distanna[2]metallocenophanes of Ruthenium and Osmium

et al. 2013

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We report the molecular structures of 1,1'-dilithiometallocenes of ruthenium and osmium. These compounds served as precursors for the synthesis and subsequent structural characterization of the first [2]osmocenophanes with disilane and distannane bridges, as well as of a distanna[2]ruthenocenophane. In addition, the insertion of sulfur and selenium into the Sn-Sn bridges was studied and it was observed that the presence of the Lewis base pmdta (N,N,N',N″,N″-pentamethyldiethylenetriamine) dramatically accelerates the reaction.

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Synthesis and Structure of New [3]Silametallocenophanes of Group 8 Metals

Cited by 5 publications

References 46 publications

Cooperative Bimetallic Asymmetric Catalysis: Comparison of a Planar Chiral Ruthenocene Bis-Palladacycle to the Corresponding Ferrocene

Cooperative Bimetallic Asymmetric Catalysis: Comparison of a Planar Chiral Ruthenocene Bis-Palladacycle to the Corresponding Ferrocene

Disilane-bridged architectures: an emerging class of molecular materials

Structure and Reactivity of Distanna[2]metallocenophanes of Ruthenium and Osmium

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