抽象的 用各种底物研究了酚(3当量)与各种取代的苯基N,N-二乙基氨基甲酸酯的氧化交叉偶联。在三氟乙酸中使用Pd(OAc)2作为催化剂(20摩尔%),在化学计量的氧化剂中使用K 2 S 2 O 8作为溶剂(50°C,2 h)。除非苯基取代基的吸电子性(CN)太强,否则在苯环上不具有或具有取代基的氨基甲酸酯(Me,Ph,Cl,OMe)进行反应。交叉偶联仅在相对于氨基甲酸酯基团的邻位发生。苯酚的区域选择性(邻位或对位)羟基)主要由空间因素决定。特定的氨基甲酸酯/苯酚组合物的收率高达60-70%。 用各种底物研究了酚(3当量)与各种取代的苯基N,N-二乙基氨基甲酸酯的氧化交叉偶联。在三氟乙酸中使用Pd(OAc)2作为催化剂(20摩尔%),在化学计量的氧化剂中使用K 2 S 2 O 8作为溶剂(50°C,2 h)。除非苯基取代基的吸电子性(CN)太强,否则在苯环上不具有或具有取代基的氨基甲酸酯(M
Nickel-Catalyzed Ipso-Borylation of Silyloxyarenes via C–O Bond Activation
作者:Wesley L. Pein、Eric M. Wiensch、John Montgomery
DOI:10.1021/acs.orglett.1c01280
日期:2021.6.18
The conversion of silyloxyarenes to boronic acid pinacol esters via nickel catalysis is described. In contrast to other borylation protocols of inert C–O bonds, the method is competent in activating the carbon–oxygen bond of silyloxyarenes in isolated aromatic systems lacking a directing group. The catalytic functionalization of benzyl silyl ethers was also achieved under these conditions. Sequential
The directed ortho borylation of phenol derivatives protected with an N,N-diethylcarbamoyl group was efficiently catalyzed by an immobilized monophosphine-Ir system, which was prepared in situ from [Ir(OMe)(cod)](2) and a silica-supported, compact phosphine. The utility of the carbamoyloxy group as a leaving group for metal-catalyzed cross-coupling reactions was demonstrated by its utilization in the synthesis of a terphenyl derivative.
<i>Ortho</i>- and <i>Para</i>-Selective Ruthenium-Catalyzed C(sp<sup>2</sup>)–H Oxygenations of Phenol Derivatives
作者:Weiping Liu、Lutz Ackermann
DOI:10.1021/ol401535k
日期:2013.7.5
Versatile ruthenium catalysts allowed for efficient direct oxygenations of aryl carbamates under remarkably mild reaction conditions. In addition to chelation-assisted C-H activation, the optimized ruthenium catalyst proved amenable to para-selective hydroxylations of anisoles without Lewis basic directing groups.