Ligand-Controlled Chemoselective C(acyl)–O Bond vs C(aryl)–C Bond Activation of Aromatic Esters in Nickel Catalyzed C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Cross-Couplings
converted into the alkylated arenes and ketone products, respectively. The utility of this newly developed protocol was demonstrated by its wide substrate scope, broad functional group tolerance and application in the synthesis of keyintermediates for the synthesis of bioactive compounds. DFT studies on the oxidative addition step helped rationalizing this intriguing reaction chemoselectivity: whereas
Direct Synthesis of Ketones from Methyl Esters by Nickel‐Catalyzed Suzuki–Miyaura Coupling
作者:Yan‐Long Zheng、Pei‐Pei Xie、Omid Daneshfar、Kendall N. Houk、Xin Hong、Stephen G. Newman
DOI:10.1002/anie.202103327
日期:2021.6.7
direct conversion of alkyl esters to ketones has been hindered by the sluggish reactivity of the starting materials and the susceptibility of the product towards subsequent nucleophilic attack. We have now achieved a cross-coupling approach to this transformation using nickel, a bulky N-heterocyclic carbene ligand, and alkyl organoboron coupling partners. 65 alkylketonesbearing diverse functional groups
烷基酯向酮的直接转化受到起始材料缓慢的反应性和产物对随后亲核攻击的敏感性的阻碍。我们现在已经使用镍、一种庞大的 N-杂环卡宾配体和烷基有机硼偶联伙伴实现了这种转化的交叉偶联方法。用这种方法合成了 65 个带有不同官能团和杂环支架的烷基酮。对于带有易于被 Ni 裂解的其他键的多功能底物的 C(酰基)-O 键活化,观察到催化剂控制的化学选择性,包括芳醚、芳基氟和 N-Ph 酰胺官能团。密度泛函理论计算为 Ni 0 /Ni II提供了机械支持 催化循环,并证明稳定的大催化剂和底物之间的非共价相互作用对反应的成功至关重要。
Arylation of Aldehydes To Directly Form Ketones via Tandem Nickel Catalysis
作者:Chuanhu Lei、Daoyong Zhu、Vicente III Tiu Tangcueco、Jianrong Steve Zhou
DOI:10.1021/acs.orglett.9b01782
日期:2019.8.2
both aliphatic and aromatic aldehydes proceeds with air-stable (hetero)arylboronic acids, with an exceptionally wide substrate scope. The neutral condition tolerates acidic hydrogen and sensitive polar groups and also preserves α-stereocenters of some chiral aldehydes. Interestingly, this nickel(0) catalysis does not follow common 1,2-insertion of arylmetal species to aldehydes and β-hydrogen elimination
Dual Functionalization of α‐Monoboryl Carbanions through Deoxygenative Enolization with Carboxylic Acids
作者:Wei Sun、Lu Wang、Chungu Xia、Chao Liu
DOI:10.1002/anie.201801679
日期:2018.5.4
1‐diborylalkanes through deoxygenative enolization with carboxylicacids was developed. 1,1‐Diborylalkanes were activated by MeLi to generate α‐monoboryl carbanions. In situ IR spectroscopy indicated an interaction between carboxylicacid and 1,1‐diborylalkane before addition of the activation reagent. Release of the active α‐monoboryl carbanion from the masked form was necessary for its reaction with carboxylate
Herein, we first present a nickel-catalyzed arylation and alkenylation of tert-cyclobutanols with aryl/alkenyl triflates via a C–Cbondcleavage. An array of γ-substituted ketones was obtained in moderate-to-good yields, thus featuring earth-abundant nickel catalysis, broad substrate scope, and simple reaction conditions. Preliminary mechanistic experiments indicated that β-carbon elimination pathways