A nickel‐catalyzed alkylation of polycyclic aromatic methyl ethers as well as methyl enol ethers with B‐alkyl 9‐BBN and trialkylborane reagents that involves the cleavage of stable C(sp2)−OMe bonds is described. The transformation has a wide substrate scope and good chemoselectivity profile while proceeding under mild reaction conditions; it provides a versatile way to form C(sp2)−C(sp3) bonds that
Metal-Catalyzed Dealkoxylative C<sub>aryl</sub>C sp 3 Cross-Coupling-Replacement of Aromatic Methoxy Groups of Aryl Ethers by Employing a Functionalized Nucleophile
The direct replacement of aromaticmethoxygroups with activated carbon nucleophiles would give rise to novel synthetic pathways for targeted and diversity‐oriented syntheses. We demonstrate here that this transformation can be achieved in a one‐step reaction involving a bifunctional organolithium nucleophile in combination with a CArOMe bond‐cleaving nickel catalyst. The resulting products are stable
Nickel(0)-Catalyzed Inert C–O Bond Functionalization: Organo Rare-Earth Metal Complex as the Coupling Partner
作者:Xiangqian Yan、Fanzhi Yang、Guilong Cai、Qingwei Meng、Xiaofang Li
DOI:10.1021/acs.orglett.7b03753
日期:2018.2.2
An organo rare-earth metalcomplex has been employed as a highly efficient nucleophile in Ni(0)-catalyzed C–O bond functionalization. The optimized catalytic system which consists of Ni(cod)2, PCy3, and t-BuONa could smoothly convert 1 equiv of naphthyl ethers to alkylated naphthalene analogues with 0.4 equiv of Ln(CH2SiMe3)3(THF)2, delivering good to excellent yields. The reaction system could also
Lewis Acid Assisted Nickel‐Catalyzed Cross‐Coupling of Aryl Methyl Ethers by C−O Bond‐Cleaving Alkylation: Prevention of Undesired β‐Hydride Elimination
In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C−O bond‐cleaving alkylation, for the first time without the limiting β‐hydride elimination. This new nickel‐catalyzed dealkoxylative alkylation method enables powerful orthogonal synthetic strategies for the transformation of a variety of naturally occurring and easily accessible anisole
Ni-Catalyzed Reduction of Inert C−O Bonds: A New Strategy for Using Aryl Ethers as Easily Removable Directing Groups
作者:Paula Álvarez-Bercedo、Ruben Martin
DOI:10.1021/ja106943q
日期:2010.12.15
An efficient Ni-catalyzed protocol for the reductive cleavage of inert C-O bonds has been developed. The method is characterized by its simplicity and wide scope, thereby allowing the use of aryl ethers as easily removable directing groups in organic synthesis.