secondary benzylic alcohols via tandem Ni-catalyzed cross-coupling reactions of aromatic 2-pyridyl esters with alkyl zinc reagents and carbonyl group reduction by Ni–H species is achieved. Preliminary mechanistic studies reveal that the Ni–H species is generated in situ via β-hydride elimination of the Negishi reagents. The reaction is catalyzed by bench-stable nickel salts under mild conditions with
[reaction: see text] The palladium-catalyzed coupling reaction of 2-pyridyl esters with organoboroncompounds is described. The reaction is compatible with various functional groups and proceeds under mild reaction conditions. The coordination of the nitrogen atom to Pd is a key step for efficient reaction.
Nickel-Catalyzed Three-Component Alkylacylation of Alkenes Enabled by a Photoactive Electron Donor–Acceptor Complex
作者:Xiaoxiang Xi、Yukun Chen、Weiming Yuan
DOI:10.1021/acs.orglett.2c01237
日期:2022.6.10
An electron donor–acceptor complex-enabled, nickel-catalyzed three-component net-reductive 1,2-alkylacylation of alkenes is developed. This conjunctive reductive acyl cross-coupling process obviates the use of an exogenous photocatalyst and a stoichiometric metal-based reductant, affording various synthetically useful 1,3-dicarbonylcompounds in good yields with a broad substrate scope and excellent
A novel metal- and catalyst-free dearomative reaction of 2-oxypyridines to construct gem-difluoromethylenated N-substituted 2-pyridones has been developed. The reaction involves an attractive acyl rearrangement from O to CF2 of difluorocarbene-derived pyridinium ylides, which provides a new strategy for the direct introduction of the gem-difluoromethylene group with high efficiency and selectivity as
Ni-catalyzed enantioselective three-component reductive alkylacylation of alkenes: modular access to structurally complex α-amino ketones
作者:Jichao Xiao、Tingting Jia、Shuang Chen、Mengxiao Pan、Xingwei Li
DOI:10.1039/d4sc04561k
日期:——
scope and excellent functional group tolerance using readily available starting materials and allowing rapid access to structurally complex α-amino ketone derivatives in high enantioselectivity. A suitable chiral biimidazoline ligand together with additional chelation of the amide carbonyl group in a Ni alkyl intermediate facilitates the enantioselective control by suppressing the background reaction
手性α-氨基酮作为功能分子已得到广泛应用。以叔烷基溴和羧酸衍生的亲电子试剂作为偶联剂,实现了镍催化、对映选择性、完全分子间三组分N-酰基烯酰胺的 1,2-烷基酰化。这种还原偶联策略操作简单,使用易于获得的起始材料,表现出广泛的底物范围和优异的官能团耐受性,并允许以高对映选择性快速获得结构复杂的 α-氨基酮衍生物。合适的手性双咪唑啉配体与 Ni 烷基中间体中酰胺羰基的额外螯合有助于通过抑制背景反应来促进对映选择性控制,从而实现优异的对映选择性。机理研究表明自由基物种的中介作用。