A general Pd-catalyzed α- and γ-benzylation of aldehydes for the formation of quaternary centers
作者:Ivan Franzoni、Laure Guénée、Clément Mazet
DOI:10.1039/c5ob00702j
日期:——
A palladium-catalyzed benzylation of α-branched aldehydes has been developed using benzyl methyl carbonates. The method gives access to congested quaternary centers in the vicinity of one of the most sensitive carbonyl functionalities and displays unprecedented generality with respect to both coupling partners. Evidence for the direct involvement of a Pd-η3-benzyl intermediate is provided. Extension
The title reaction is found to proceed in the presence of a palladium catalyst and in the absence of any activator. Various functional groups are tolerated to give a diverse range of 1,4-diene and diarylmethane products, which are ubiquitous units of natural products and pharmaceuticals.
Transformation of Carbonates into Sulfones at the Benzylic Position via Palladium-Catalyzed Benzylic Substitution
作者:Ryoichi Kuwano、Yutaka Kondo、Tsuyoshi Shirahama
DOI:10.1021/ol0509787
日期:2005.7.1
The nucleophilic substitution of benzylic carbonates with sodium arenesulfinates was catalyzed by the palladium complex generated in situ from [Pd(eta(3)-C3H5)Cl](2) and DPEphos [bis(2-diphenylphosphinophenyl)ether]. The catalytic reaction proceeded in DMSO at 80 degrees C and gave a variety of benzylic sulfones in high yields.
Palladium-catalyzed Benzylic Substitution of Benzyl Carbonates with Phosphorus Nucleophiles
A wide range of benzyl carbonates reacted with dimethyl phosphonate or diphenylphosphine oxide in the presence of the palladium catalyst, [Pd(η3-allyl)Cl]2–DPEphos, to give dimethyl benzylphosphonates and benzyldiphenylphosphine oxides in high yields. The catalytic phosphonylation was applied to the one-pot synthesis of alkenes from the benzyl esters.