Highly Efficient Catalytic Dimerization of Styrenes<i>via</i>Cationic Palladium(II) Complexes

Choi, Ji Hye; Kwon, Jae Kwan; RajanBabu, T. V.; Lim, Hae Ja

doi:10.1002/adsc.201300864

Cited by 19 publications

(8 citation statements)

References 54 publications

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“…Most gratifyingly, unlike many other ligand systems we have examined, there is no sign of isomerization of the primary product, 7 , to 8 even at room temperature. 5c Dimerization of the vinylarenes7 was also not observed.…”

Section: Resultsmentioning

confidence: 93%

Triarylphosphine Ligands with Hemilabile Alkoxy Groups: Ligands for Nickel(II)‐Catalyzed Olefin Dimerization Reactions. Hydrovinylation of Vinylarenes, 1,3‐Dienes, and Cycloisomerization of 1,6‐Dienes

Biswas

Zhang²,

Raya³

et al. 2014

Adv Synth Catal

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Substitution of one of the phenyl groups of triphenylphosphine with a 2-benzyloxy-, 2-benzyloxymethyl- or 2-benzyloxyethyl-phenyl moiety results in a set of simple ligands, which exhibit strikingly different behaviour in various nickel(II)-catalyzed olefin dimerization reactions. Complexes of ligands with 2-benzyloxyphenyl-, 2-benzyloxymethylphenyl-diphenylphosphine (L5 and L6 respectively) are most active for hydrovinylation (HV) of vinylarenes, with the former leading to extensive isomerization of the primary 3-aryl-1-butenes into the conjugated 2-aryl-2-butenes even at −55 °C. However, 2-benzyloxymethyl-substituted ligand L6 is slightly less active, leading up to quantitative yields of the primary products of HV at ambient temperature with no trace of isomerization, thus providing the best option for a practical synthesis of these compounds. In sharp contrast, hydrovinylation of a variety of 1,3-dienes is best catalyzed by nickel(II)-complexes of 2-benzyloxyphenyldiphenylphosphine, L5. The other two ligands, 2-benzyloxymethyl-(L6) and 2-benzyloxyethyl-diphenylphosphine (L7) are much less effective in the HV of 1,3-dienes. Nickel(II)-catalyzed cycloisomerization of 1,6-dienes into methylenecyclopentanes, a reaction mechanistically related to the other hydrovinylation reactions, is also uniquely effected by nickel(II)-complexes of L5, but not of L6 or L7. In an attempt to prepare authentic samples of the methylencyclohexane products, nickel(II)-complexes of N-heterocyclic carbene-ligands were examined. In sharp contrast to the phosphines, which give the methylenecyclopentanes, methylenecyclohexanes are the major products in the (N-heterocyclic carbene)nickel(II)-mediated reactions.

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Section: Resultsmentioning

confidence: 93%

Triarylphosphine Ligands with Hemilabile Alkoxy Groups: Ligands for Nickel(II)‐Catalyzed Olefin Dimerization Reactions. Hydrovinylation of Vinylarenes, 1,3‐Dienes, and Cycloisomerization of 1,6‐Dienes

Biswas

Zhang²,

Raya³

et al. 2014

Adv Synth Catal

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“…We hypothesize that this styrene dimer arises via a metal hydride-mediated Heck-type pathway. 15 Minor amounts of similar dimers are also observed as byproducts in reactions using Me 3 SiOTf (Table 1); however, formation of these dimers is less significant. These results suggest that the dimerization pathway becomes more competitive with increasing steric bulk of the silyl triflate, likely due to the difficulty of oxidative addition.…”

Section: Resultsmentioning

confidence: 97%

The first example of nickel-catalyzed silyl-Heck reactions: direct activation of silyl triflates without iodide additives

et al. 2014

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For the first time, nickel-catalyzed silyl-Heck reactions are reported. Using simple phosphine-supported nickel catalysts, direct activation of silyl triflates has been achieved. These results contrast earlier palladium-catalyzed systems, which require iodide additives to activate silyl-triflates. These nickel-based catalysts exhibit good functional group tolerance in the preparation of vinyl silanes, and unlike earlier systems, allows for the incorporation of trialkylsilanes larger than Me3Si.

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“…The head-to-tail dimerization of styrenes ( Fig. 5A ) is a useful reaction to obtain branched styrenes in a 100% atom-economical manner, 9 and it has been catalyzed previously with, among others, Pd triflate complexes, 10 a combination of metal complexes such as Pd/In triflate/phosphines 11 or Co/Zn, 12 and with Fe(NTf 2 ) 3 , 13 all of them in homogenous solution. Thus, a simple solid catalyst for this reaction remains a challenge.…”

Section: Resultsmentioning

confidence: 99%

Bimetallic nanosized solids with acid and redox properties for catalytic activation of C–C and C–H bonds

et al. 2017

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Highly Efficient Catalytic Dimerization of StyrenesviaCationic Palladium(II) Complexes

Abstract: A highly efficient head-to-tail dimerization of a styrene was developed using a cationic palladi-

Cited by 19 publications

References 54 publications

Triarylphosphine Ligands with Hemilabile Alkoxy Groups: Ligands for Nickel(II)‐Catalyzed Olefin Dimerization Reactions. Hydrovinylation of Vinylarenes, 1,3‐Dienes, and Cycloisomerization of 1,6‐Dienes

Triarylphosphine Ligands with Hemilabile Alkoxy Groups: Ligands for Nickel(II)‐Catalyzed Olefin Dimerization Reactions. Hydrovinylation of Vinylarenes, 1,3‐Dienes, and Cycloisomerization of 1,6‐Dienes

The first example of nickel-catalyzed silyl-Heck reactions: direct activation of silyl triflates without iodide additives

Bimetallic nanosized solids with acid and redox properties for catalytic activation of C–C and C–H bonds

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