An efficient ligand-free Pd(OAc)2-catalyzed selectivearylation of pyridine N-oxides using potassium (hetero)aryltrifluoroborates as coupling partners via C–H bond activation was achieved in the presence of TBAI. This approach has a broad substrate scope and shows moderate to high yields.
Decarboxylative cross‐coupling reactions of substituted 2‐carboxyazine N‐oxides, with a variety of (hetero)arylhalides, by bimetallic Pd0/CuI and Pd0/AgI catalysis are reported. Two possible pathways, a conventional bimetallic‐catalyzed decarboxylative arylation, as well as a protodecarboxylative/direct CH arylation sequence have been considered. These methods provide the first general decarboxylative
据报道,通过双金属Pd 0 / Cu I和Pd 0 / Ag I催化,取代的2-羧嗪N-氧化物与各种(杂)芳基卤化物发生脱羧交叉偶联反应。两种可能的途径,传统的双金属催化的芳基化脱羧,以及一个protodecarboxylative /直接ç ħ芳基化序列已被考虑。这些方法为2-羧嗪系列提供了第一个通用的脱羧芳基化方法。
Silver-Catalyzed 2-Pyridyl Arylation of Pyridine N-Oxides with Arylboronic Acids at Room Temperature
A novel direct arylation of pyridineN-oxides with arylboronic acids through C-H functionalization has been developed. This new reaction is performed at room temperature using catalytic silver(l) nitrate in the presence of potassium persulfate and give 2-pyridyl arylation derivatives of pyridineN-oxides.
Synthesis of 2-(2′-hydroxyphenyl)pyridine-N-oxide and its thermal decomposition as a model reaction of orellanine deoxidation
作者:Wieslaw Z. Antkowiak、Wieslaw P. Gessner
DOI:10.1016/0040-4039(84)80062-3
日期:——
2-Methoxyphenylmagnesium bromide was reacted with 2-nitropyridine-N-oxide and demethylated to give 2-(2′-hydroxyphenyl)pyridine-N-oxide (II) which was found to undergo a thermaldeoxidation to the free base (VI); the process is interpreted as a [1.5] oxygen shift followed by decomposition of the hydroperoxide intermediate.