Iminyl-Radicals by Oxidation of α-Imino-oxy Acids: Photoredox-Neutral Alkene Carboimination for the Synthesis of Pyrrolines
作者:Heng Jiang、Armido Studer
DOI:10.1002/anie.201706270
日期:2017.9.25
α‐imino‐oxy propionic acids for the generation of iminyl radicals has been accomplished through the use of Ir(dFCF3ppy)2(dtbbpy)PF6 as a photoredox catalyst. Different from visible‐light‐promoted homolysis and single‐electron reduction of oxime derivatives, this strategy provides a novel catalytic cycle for alkene carboimination through a sequence comprising N‐radical generation, iminyl radical cyclization,
α-Aminoxy-Acid-Auxiliary-Enabled Intermolecular Radical γ-C(sp<sup>3</sup>
)−H Functionalization of Ketones
作者:Heng Jiang、Armido Studer
DOI:10.1002/anie.201712066
日期:2018.2.5
site‐specific intermolecular γ‐C(sp3)−H functionalization of ketones has been developed using an α‐aminoxy acid auxiliary applying photoredox catalysis. Regioselective activation of an inert C−H bond is achieved by 1,5‐hydrogen atom abstraction by an oxidatively generated iminyl radical. Tertiary and secondary C‐radicals thus formed at the γ‐position of the imine functionality undergo radicalconjugate addition
Transition‐Metal‐Free Three‐Component Radical 1,2‐Amidoalkynylation of Unactivated Alkenes
作者:Heng Jiang、Armido Studer
DOI:10.1002/chem.201805490
日期:——
A transition‐metal‐freeradical 1,2‐amidoalkynylation of unactivated alkenes is presented. α‐Amido‐oxy acids were used as amidyl radical precursors, which were oxidized by an organic photoredox catalyst (4CzlPN). The electrophilic N‐radicals chemoselectively reacted with various aliphatic alkenes and the adduct radicals were then trapped by ethynylbenziodoxolone (EBX) reagents to eventually provide
Metal-free visible light-promoted synthesis of isothiazoles: a catalytic approach for N–S bond formation from iminyl radicals under batch and flow conditions
applying photoredoxcatalysis. This simple strategy features mild conditions, broad scope and wide functional group tolerance representing a new enviromentally friendly option to prepare these highly valuable heterocycles. Furthermore, the synthetic value of the method is highlighted by the preparation of a natural product derivative and the implementation of the reaction in a continuousflow setup.
Amidyl Radicals by Oxidation of α‐Amido‐oxy Acids: Transition‐Metal‐Free Amidofluorination of Unactivated Alkenes
作者:Heng Jiang、Armido Studer
DOI:10.1002/anie.201804966
日期:2018.8.13
three‐component transition‐metal‐free amidofluorination of unactivated alkenes and styrenes is presented. α‐Amido‐oxy acids are introduced as efficient and easily accessible amidyl radical precursors that are oxidized by a photoexcited organic sensitizer (Mes‐Acr‐Me) to the corresponding carboxyl radical. Sequential CO2 and aldehyde/ketone fragmentation leads to an N‐centered radical that adds to an