42461-65-4Relevant articles and documents
Visible-Light Controlled Divergent Catalysis Using a Bench-Stable Cobalt(I) Hydride Complex
Beltran, Frédéric,Bergamaschi, Enrico,Teskey, Christopher J.
supporting information, p. 5180 - 5184 (2020/04/22)
While the use of visible light in conjunction with transition metal catalysis offers powerful opportunities to switch between on/-off states of catalytic activity, the next frontier would be the ability to switch the actual function of the catalyst and resulting products. Here we report such an example of multi-dimensional catalysis. Featuring an easily prepared, bench-stable cobalt(I) hydride complex in conjunction with pinacolborane, we can switch the reaction outcome between two widely employed transformations, olefin migration and hydroboration, with visible light as the trigger.
An alternative mechanism for the cobalt-catalyzed isomerization of terminal alkenes to (Z)-2-alkenes
Schmidt, Anastasia,N??dling, Alexander R.,Hilt, Gerhard
supporting information, p. 801 - 804 (2015/03/04)
The cobalt-catalyzed selective isomerization of terminal alkenes to the thermodynamically less-stable (Z)-2-alkenes at ambient temperatures takes place by a new mechanism involving the transfer of a hydrogen atom from a Ph2PH ligand to the starting material and the formation of a phosphenium complex, which recycles the Ph2PH complex through a 1,2-H shift.
Double-Bond Isomerization: Highly Reactive Nickel Catalyst Applied in the Synthesis of the Pheromone (9 Z,12 Z)-Tetradeca-9,12-dienyl Acetate
Weber, Felicia,Schmidt, Anastasia,R?se, Philipp,Fischer, Michel,Burghaus, Olaf,Hilt, Gerhard
supporting information, p. 2952 - 2955 (2015/06/30)
A highly reactive nickel catalyst comprising NiCl2(dppp) or NiCl2(dppe) with zinc powder, ZnI2 and Ph2PH, was applied in the isomerization of terminal alkenes to Z-2-alkenes. The double-bond geometry of the 2-alkene can be controlled via the reaction temperature to yield the 2-Z-alkenes in excellent yields and high Z-selectivities. The formation of other constitutional isomers, such as 3-alkenes, is suppressed on the basis of the proposed mechanism via a 1,2-hydride shift from the metal to the Ph2P ligand. The nickel-catalyzed isomerization reaction was then applied in the synthesis of (9Z,12Z)-tetradeca-9,12-dienyl acetate, a pheromone with a 2Z,5Z-diene subunit.
Rhodium-catalyzed allylation of benzyl acetates with allylsilanes
Onodera, Gen,Yamamoto, Eriko,Tonegawa, Shota,Iezumi, Makoto,Takeuchi, Ryo
scheme or table, p. 2013 - 2021 (2011/10/09)
Benzyl acetate reacted with allyltrimethylsilane to give an allylation product in the presence of a catalytic amount of the (cyclooctadiene)rhodium(I) chloride dimer {[Rh(cod)Cl]2}, sodium tetrakis[3,5- bis(trifluoromethyl)phenyl]borate (NaBARF), and triphenyl phosphite [P(OPh) 3] in refluxing 1,2-dichloroethane. Primary, secondary and tertiary benzyl acetates could be used for the reaction. Moreover, allylation of gem-benzyl acetate was possible with [Rh(cod)Cl]2, NaBARF, and P(OPh)3. Monoallylation and diallylation of gem-benzyl acetate could be controlled by altering the reaction conditions. Cationic rhodium species generated in situ act as a Lewis acid catalyst to give a benzyl carbocation by elimination of the acetoxy group from the benzylic carbon. Copyright
Identification of a valuable kinetic process in copper-catalyzed asymmetric allylic alkylation
Langlois, Jean-Baptiste,Alexakis, Alexandre
supporting information; experimental part, p. 1877 - 1881 (2011/04/16)
Copper bottomed: The application of a previously described process of dynamic kinetic asymmetric transformation to acyclic substrates allowed the identification of a relevant kinetic process in the title reaction (see scheme; CuTC= copper(I) thiophencarboxylate, Naphth= naphthyl). The optimization of the reaction conditions and generality of the method, as well as mechanistic considerations are disclosed.
Nickel(II) compounds derived from tripod ligands: Efficient catalysts for the stereoselective heterodimerization of styrene and propene
Faissner, Ralf,Huttner, Gottfried
, p. 2239 - 2244 (2007/10/03)
The tripod ligands RCH2C(CH2X)(CH2Y)(CH2Z) form tetracoordinate compounds with NiHal2. If two of the donor functions X, Y, Z are phosphanes, square-planar coordination is observed. In contrast, donor sets X,Y,Z = P,N,N or N,N,N form tetrahedral compounds, by P,N or N,N coordination, that are active in the catalysis of olefin oligomerization with MAO as a co-catalyst. These catalyst systems are also active in the stereoselective heterodimerization of olefins. The co-dimerization of styrene and propene by these systems leads to 4-phenyl-2-pentene almost exclusively, with regioselectivities up to 98% and (E)/(Z) ratios of up to 95:5, surpassing other reported catalysts for this process. The products of these catalytic transformations have been fully characterized by GC/MS techniques as well by isolation, NMR and MS characterization of the pure compounds. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Heterodimerization of propylene and vinylarenes: Functional group compatibility in a highly efficient Ni-catalyzed carbon-carbon bond-forming reaction
Jin, Jian,Rajanbabu
, p. 2145 - 2151 (2007/10/03)
Unlike heterodimerization reactions of ethylene and vinylarenes, no such synthetically useful reactions using propylene are known. We find that propylene reacts with various vinylarenes in the presence of catalytic amounts of [(allyl)NiBr]2, tr
Alkylation of Allylic Derivatives. 3. The Regiochemistry of Alkylation of the Isomeric trans-α,γ-Methylphenylallyl Acetates with Lithium Dialkyleuprates
Goering, Harlan N.,Seitz, Earl P.,Tseng, Chung Chyi
, p. 5304 - 5308 (2007/10/02)
Alkylation of the isomeric trans-α,γ-methylphenylallyl acetates (1-OAc and 2-OAc) with lithium dimethylcuprate or di-n-butylcuprate is regioselective but not regiospecific.Both isomers give essentially the same product mixture which contains 95percent of the trans conjugated alkylation product (3).The starting acetates do not rearrange under the conditions for these reactions.These results show that the isomeric acetate give the same product-forming intermediate(s).Presumably the key intermediate that is common to the two isomers is a ?-allyl copper(III).
