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
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
High yielding alkylations of unactivated sp<sup>3</sup>and sp<sup>2</sup>centres with alkyl-9-BBN reagents using an NHC-based catalyst: Pd-PEPPSI-IPr
作者:Cory Valente、Sylvia Baglione、David Candito、Christopher J. O'Brien、Michael G. Organ
DOI:10.1039/b715081d
日期:——
High yielding, room temperature cross couplings of unactivated alkyl bromides and aryl bromides/chlorides with alkyl-9-BBN reagents has been achieved using an NHC-based catalyst (Pd-PEPPSI-IPr) via a general, functional-group tolerant and easily implemented protocol.
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。
Phosphaadamantanes as Ligands for Palladium Catalyzed Cross-Coupling Chemistry: Library Synthesis, Characterization, and Screening in the Suzuki Coupling of Alkyl Halides and Tosylates Containing β-Hydrogens with Boronic Acids and Alkylboranes
作者:Tim Brenstrum、David A. Gerristma、George M. Adjabeng、Christopher S. Frampton、James Britten、Alan J. Robertson、James McNulty、Alfredo Capretta
DOI:10.1021/jo048875+
日期:2004.10.1
allowed for the rapid determination of the most suitable ligand, specifically 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane, for facilitating Suzuki-type couplings of alkylhalides or tosylates containing β-hydrogens with either boronic acids or alkylboranes.