The functionalization of a cascade of C(sp<sup>2</sup>)–H/C(sp<sup>3</sup>)–H bonds: synthesis of fused dihydropyrazoles via visible-light photoredox catalysis
The functionalization of a cascade of C(sp2)-H/C(sp3)-H bonds in aldehyde hydrazones with simple 2,2-dibromo-1,3-dicarbonyls was achieved via visible-light photoredoxcatalysis. This method, which involves free radical addition, polar crossover and...
Relay photocatalytic cascade reactions: synthesis of indolo[2,1-<i>a</i>]isoquinoline derivatives <i>via</i> double C(sp<sup>3</sup>)–H bond functionalization
作者:Jian Cheng、Jin Xie、Chengjian Zhu
DOI:10.1039/c7cc09820k
日期:——
A relay photoredox catalysis strategy concomitant with [1,5] hydrogen atom transfer has been applied in the construction of a biologically important indolo[2,1-a]isoquinoline framework via a cascade reaction. This reaction enables double C(sp3)–H bond functionalization and formation of two carbon–carbondouble bonds from readily available starting materials in an efficient and step-economical manner
与[1,5]氢原子转移相伴的继发性光氧化还原催化策略已通过级联反应用于构建具有重要生物学意义的吲哚[2,1- a ]异喹啉骨架。该反应可实现双C(sp 3)-H键官能化,并以有效和分步经济的方式从容易获得的起始原料中形成两个碳-碳双键。
Photocatalytic Regioselective [2 + 2 + 1] Radical Annulation of Alkenes with <i>tert</i>-Butyl Nitrite and <i>gem</i>-Dihalides
作者:Jiupeng Liu、Shuo Tang、Huayan Xu、Ruoyu Zhang、Jingjing Zhao、Puyu Zhang、Pan Li
DOI:10.1021/acs.orglett.2c03635
日期:2022.12.30
A visible-light photocatalytic regioselective [2 + 2 + 1] radical annulation reaction of alkenes, tert-butyl nitrite, and gem-dihalides has been developed. The protocol provides an efficient and practical approach to obtain isoxazolines in good yields under mild conditions. Significantly, gem-dihalides serve as C1 synthons, while cheap tert-butyl nitrite acts as an ideal “N–O” synthon.
Photoredox Divergent 1,2-Difunctionalization of Alkenes with <i>gem</i>-Dibromides
作者:Jian Cheng、Yixiang Cheng、Jin Xie、Chengjian Zhu
DOI:10.1021/acs.orglett.7b03371
日期:2017.12.1
The redox neutral photocatalytic divergent radical 1,2-difunctionalization of a wide array of structurally varied alkenes with gem-dibromides is presented. On the basis of the electronic effect of alkenes, predictable 1,2-carboxygenation and 1,2-carbohalogenation of alkenes are readily available regardless of steric effect. This protocol affords a practical approach to the biologically important furan skeleton. It is distinguished by good regioselectivity, good functional group compatibility, and late-stage modification and thus signifies an important step forward to divergent radical difunctionalization of alkenes.