Synthesis of some ketones via nano-nickel oxide catalyzed acylation of arylzinc reagents; strategy involving the use of mixed (methyl)(aryl)zincs
Nano-NiO catalyzed acylation of mixed (methyl)(aryl)zincs with aromatic acyl halides in THF at room temperature provides a new facile route for aryl–aroyl coupling. Among NiCl2 .L2 and NiCl2 .L (L = monodentate and bidentate phosphine ligand) catalysts, the lower catalyst loading of NiCl2 (dppf) may seem attractive; however, nano-NiO, being the lowest cost catalyst, is more favorable for aroylation of (methyl)(aryl)zincs. This procedure also provides a supplement to Cu and Pd catalyzed acylation of diorganozincs.
Pekel, ?zgen ?MüR,Erdik, Ender,Kalkan, Melike
p. 759 - 767
(2018/06/07)
Reactivity of mixed organozinc and mixed organocopper reagents: 11. Nickel-catalyzed atom-economic aryl-allyl coupling of mixed (n-alkyl)(aryl)zincs
Group selectivity in the allylation of mixed (n-butyl)(phenyl)zinc reagent can be controlled by changing reaction parameters. CuCN-catalyzed allylation in tetrahydrofuran (THF)-hexamethylphosphoric triamide is n-butyl selective and also γ-selective in the presence of MgCl2, whereas CuI-catalyzed allylation in THF in the presence of n-Bu3P takes place with a n-butyl transfer:phenyl transfer ratio of 23:77 and an α:γ transfer ratio of phenyl of 76:24. NiCl2(Ph3P) 2-catalyzed allylation in the presence of LiCl is phenyl selective with an α:γ ratio of 65:35. The reaction of methyl- or n-butyl(aryl)zinc reagents with an allylic electrophile in THF at room temperature in the presence of NiCl2(Ph3P)2 catalyst and LiCl as an additive provides an atom-economic alternative to aryl-allyl coupling using diarylzincs. Copyright
Kalkan, Melike
p. 725 - 732
(2014/11/08)
Diastereomeric aziridine carbinol catalyzed enantioselective arylation reaction: Toward the asymmetric synthesis of both enantiomers of chiral 3-aryl phthalide
The diastereomeric aziridine carbinols are applied, respectively, as efficient chiral ligand in the catalysis of asymmetric arylation and sequential arylation-lactonization cascade. The two diastereomers, which are facilely synthesized from the same chiral source, function as pseudo enantiomers in arylation of aromatic aldehydes providing the different enantiomers of the diarylmethanols with almost the same excellent enantioselectivities. The arylation method is also carried out in tandem with lactonization process to afford a concise synthetic approach to both enantiomers of optically active 3-aryl phthalide.