Selective Oxidative Decarbonylative Cleavage of Unstrained C(<i>sp</i><sup>3</sup>)–C(<i>sp</i><sup>2</sup>) Bond: Synthesis of Substituted Benzoxazinones
作者:Ajay Verma、Sangit Kumar
DOI:10.1021/acs.orglett.6b02142
日期:2016.9.2
A transition metal (TM)-free practical synthesis of biologically relevant benzoxazinones has been established via a selective oxidative decarbonylative cleavage of an unstrained C(sp3)–C(sp2) bond employing iodine, sodium bicarbonate, and tbutyl hydroperoxide in DMSO at 95 °C. Control experiments and Density Functional Theory (DFT) calculations suggest that the reaction involves a [1,5]H shift and
procedure for the thermo-promoted reactions of anthranil with different substrates was developed. The catalyst-free process affords various useful building blocks with good to moderate yields. This chemistry enables several step- and cost-effective approaches for biologically interesting molecules and provides an efficient platform for the investigation of untapped reactions at high temperature.
Direct activation of sp2 C–H bonds by a palladium catalyst has received significant attention in organic chemistry. However, most of these C–Hactivation reactions are carried out in hazardous solvents. Herein we report a novel solvent-free direct sp2 C–Hbond functionalization (oxygenation) method using Pd(II)/Al2O3 catalysis of oxo-benzoxazine derivatives with good to excellent yields, and demonstrate
钯催化剂直接活化sp 2 C-H键在有机化学中受到了广泛关注。然而,大多数这些 C-H 活化反应是在危险溶剂中进行的。在此,我们报道了一种使用 Pd( II )/Al 2 O 3催化氧代苯并恶嗪衍生物的新型无溶剂直接 sp 2 C-H 键官能化(氧化)方法,并证明了其在合成药学上重要的化合物。
TBHP/CoCl<sub>2</sub>-Mediated Intramolecular Oxidative Cyclization of<i>N</i>-(2-Formylphenyl)amides: An Approach to the Construction of 4<i>H</i>-3,1-Benzoxazin-4-ones
作者:Junchao Yu、Daisy Zhang-Negrerie、Yunfei Du
DOI:10.1002/ejoc.201501359
日期:2016.1
The intramolecular oxidativecyclization of N-(2-formylphenyl)amides has been realized through an oxidative C(sp2)–O(sp2) bond-forming reaction between an aldehyde carbon and amide oxygen. This new strategy, which uses tert-butyl hydroperoxide (TBHP) as an oxidant and CoCl2 as the catalyst, allows for the efficient Co-catalyzed synthesis of useful benzoxazin-4-one derivatives and features readily available
An efficient protocol for the introduction of acetoxy and hydroxy functionalities on unactivated aryl sp2 carbons of oxobenzoxazine derivatives via an ortho-C–H activation reaction using a palladium catalyst has been developed for the first time. Interestingly, this intermolecular C–H functionalization reaction takes place in a facile and simple manner with high chemo- and site selectivity.