Rational Design of an Iron‐Based Catalyst for Suzuki–Miyaura Cross‐Couplings Involving Heteroaromatic Boronic Esters and Tertiary Alkyl Electrophiles
作者:Michael P. Crockett、Alexander S. Wong、Bo Li、Jeffery A. Byers
DOI:10.1002/anie.201914315
日期:2020.3.23
cross‐coupling reactions between a variety of alkyl halides and unactivated aryl boronicesters using a rationally designed iron‐based catalyst supported by β‐diketiminate ligands are described. High catalyst activity resulted in a broad substrate scope that included tertiary alkyl halides and heteroaromatic boronicesters. Mechanistic experiments revealed that the iron‐based catalyst benefited from the
Dual role of benzophenone enables a fast and scalable C-4 selective alkylation of pyridines in flow
作者:Jesús Sanjosé-Orduna、Rodrigo C. Silva、Fabian Raymenants、Bente Reus、Jannik Thaens、Kleber T. de Oliveira、Timothy Noël
DOI:10.1039/d2sc04990b
日期:——
allows preparation of said C-4 alkylated pyridines. The process involves a photochemical hydrogen atom transfer (HAT) event to generate the carbon-centered radicals needed to alkylate the C-2 blocked pyridine. In a two-step streamlined flow process, this light-mediated alkylation step is combined with a nearly instantaneous inline removal of the blocking group. Notably, cheap benzophenone plays a dual
C4-selective decyanoalkylation has been established to access diverse 4-alkylpyridines in one step. The reaction proceeds through the single electron reduction/radical–radical coupling tandem process under mild electrolytic conditions, achieving the cleavage of the C(sp2)–CN bond and the formation of C(sp3)–C(sp2). The practicality of this protocol is illustrated by no sacrificial anodes, a broad substrate
Nickel-Catalyzed Cross-Coupling of Potassium Aryl- and Heteroaryltrifluoroborates with Unactivated Alkyl Halides
作者:Gary A. Molander、O. Andreea Argintaru、Ioana Aron、Spencer D. Dreher
DOI:10.1021/ol102717x
日期:2010.12.17
A method for the cross-coupling of alkyl electrophiles with various potassium aryl- and heteroaryltrifluoroborates has been developed. Nearly stoichiometric amounts of organoboron species could be employed to cross-couple a large variety of challenging heteroaryl nucleophiles. Several functional groups were tolerated on both the electrophilic and the nucleophilic partners. Chemoselective reactivity of C(sp(3))-Br bonds in the presence of C(sp(2))-Br bonds was achieved.
Photoredox-catalysed regioselective synthesis of C-4-alkylated pyridines with <i>N</i>-(acyloxy)phthalimides
作者:Zhucheng Zhang、Qian He、Xiaofei Zhang、Chunhao Yang
DOI:10.1039/d2ob00123c
日期:——
method of direct C-4 selective alkylation of pyridines under visible light irradiation at room temperature has been reported, using simple maleate-derived pyridinium salts as pyridine precursors and the readily available carboxylic acid-derived N-(acyloxy)phthalimides as alkyl radical precursors, affording good to excellent yields without using stoichiometric oxidants and acids. A broad range of primary