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
Asymmetric Alkyl−Alkyl Cross-Couplings of Unactivated Secondary Alkyl Electrophiles: Stereoconvergent Suzuki Reactions of Racemic Acylated Halohydrins
作者:Nathan A. Owston、Gregory C. Fu
DOI:10.1021/ja105924f
日期:2010.9.1
A method for asymmetric alkyl-alkylSuzuki reactions of unactivatedsecondaryalkyl electrophiles, specifically, cross-couplings of racemic acylated halohydrins with alkylborane reagents, has been developed. A range of protected bromohydrins, as well as a protected chlorohydrin and a homologated bromohydrin, are coupled in good ee by a catalyst derived from commercially available components.
已开发出一种用于未活化仲烷基亲电试剂的不对称烷基-烷基 Suzuki 反应的方法,特别是外消旋酰化卤代醇与烷基硼烷试剂的交叉偶联。一系列受保护的溴醇,以及受保护的氯醇和同系溴醇,通过衍生自市售组分的催化剂以良好的 ee 偶联。
Nickel-Catalyzed Alkoxy-Alkyl Interconversion with Alkylborane Reagents through C−O Bond Activation of Aryl and Enol Ethers
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
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。
Switchable Selectivity in the Pd-Catalyzed Alkylative Cross-Coupling of Esters
作者:Jeanne Masson-Makdissi、Jaya Kishore Vandavasi、Stephen G. Newman
DOI:10.1021/acs.orglett.8b01646
日期:2018.7.6
The Pd-catalyzed cross-coupling of phenyl esters and alkyl boranes is disclosed. Two reaction modes are rendered accessible in a selective fashion by interchange of the catalyst. With a Pd–NHC system, alkyl ketones can be prepared in good yields via a Suzuki–Miyaurareaction proceeding by activation of the C(acyl)–O bond. Use of a Pd–dcype catalyst enables alkylated arenes to be synthesized by a modified