在此,我们报道了使用 TEMPO 衍生的烷氧基胺进行光氧化还原亲核(放射性)氟化,这是一类底物,可通过多种容易获得的羧酸、卤化物、烯烃、醇、醛、硼试剂和 C-H 一步获得债券。这种温和且通用的单电子途径提供了放射性标记的脂肪族氟化物,由于反应性不足和竞争性消除,应用传统的亲核取代技术通常无法获得这些氟化物。该光氧化还原过程的自动化还通过用户友好且市售的光氧化还原流反应器和放射合成平台进行了演示,因此加快了获得高摩尔活性 ( A m ) 的标记脂肪族氟化物的速度,以进行临床(前)评估。
Copper porphyrin-catalyzed construction of ether bond by cross-dehydrogenative coupling of sp [3] C–H bond with phenols bearing electron-withdrawing groups (EWG) was described for the first time. A broad range of substrates afforded different acetals in moderate to excellent yields with good functional group tolerance. The developed method is not only suitable for phenol substrates with ortho-directing
The construction of C(sp<sup>3</sup>)–O bond via copper porphyrin catalyzed cross-dehydrogenative coupling reaction: Substituent and electronic effect of the catalysts
effect of copper porphyrin catalysts on the cross-dehydrogenativecoupling (CDC) reaction between the hydroxyl group of phenol substrates and C(sp3)-H bond have been investigated. Results showed that copper porphyrin bearing electron-withdrawing, bulky steric hindrance or heteroatom of pyridyl groups could increase the catalytic activity in the reaction. 5,10,15,20-(tetrakis(4-pyridyl)porphyrin)copper
Nickel-Catalyzed Regioselective Cross-Dehydrogenative Coupling of Inactive C(sp<sup>3</sup>)–H Bonds with Indole Derivatives
作者:Li-Kun Jin、Li Wan、Jie Feng、Chun Cai
DOI:10.1021/acs.orglett.5b02217
日期:2015.10.2
A nickel-catalyzed regiosepecific C2- versus C3-oxidative cross-coupling reaction of indoles with 1,4-dioxane and other inactive C(sp3)–H bonds is described. The divergent synthesis of C(sp3)–C(sp2) bonds was achieved in satisfactory yields with di-tert-butyl peroxide (DTBP) as the oxidant, which provides an efficient strategy for the selective construction of cyclic ethers containing heteroaromatic
A novel method for the synthesis of β-nitrate ester carboxamides using non-corrosive tert-butyl nitrite (TBN) as the nitro source and easily available oxygen as the oxidant has been developed. Variously substituted 2-oxazolines were efficiently ring-opened to deliver the corresponding products in excellent yields. Notably, this reaction provides fast access to pharmaceuticals such as nicorandil.
Cross-dehydrogenative-coupling (CDC) between C–H/C–H bonds of indoles and cyclic ethers/cycloalkanes is made viable through a simple transition-metal-free pathway. With the aid of only di-tert-butyl peroxide, a number of inactive cyclic ethers and cycloalkanes can be directly coupled with indole derivatives in satisfactory yields.