Visible Light Mediated, Redox Neutral Remote 1,6-Difunctionalizations of Alkenes
作者:Wei Shu、Estíbaliz Merino、Cristina Nevado
DOI:10.1021/acscatal.8b00707
日期:2018.7.6
A photoinduced cascade strategy is presented here for the remote functionalization of alkenes under redox neutral conditions. A broad portfolio of alkyl groups has been added to double bonds to produce, upon 1,5-HAT, remote C-centered radicals which can be harvested in the presence of O- or C-nucleophiles to efficiently form Csp3–O and Csp3–Csp2 bonds at room temperature.
Photoredox-Catalyzed Remote Difunctionalizations of Alkenes To Synthesize Fluoroalkyl Ketones with Dimethyl Sulfoxide as the Oxidant
作者:Lixin Li、Haotian Luo、Zhengguang Zhao、Yong Li、Qiuju Zhou、Jing Xu、Jie Li、Yan-Na Ma
DOI:10.1021/acs.orglett.9b03594
日期:2019.11.15
remote benzyl C-H bond activation via a 1,5-H shift in a highly controlled site-selective manner and Kornblum reaction with dimethylsulfoxide as the oxidant. With this method, a broad array of fluoroalkyl groups were introduced into a double bond to produce 1,6-fluoroalkylated ketones at room temperature.
The cyclopropane ring in 2-substituted 1, 1-cyclopropanedicarboxylates was regioselectively opened by using samarium(II) diiodide (SmI2) in a hexamethylphosphoric triamide (HMPA)-tetrahydrofuran (THF) (1 : 10) system under mild and neutral conditions to give (2-substituted ethyl)malonates in moderate to good yields. The cyclopropane ring in 2-substituted cyclopropanecarboxylates or 2-substituted 3-(trimethylsilyl)cyclopropanecarboxylates was similarly cleaved regioselectively by using SmI2 in a HMPA-THF (1 : 1) system to give 4-arylbutyrates or 4-aryl-3-(trimethylsilyl)butyrates in 16-89% yields. The reaction mechanism of these ring-opening reactions is discussed.
The combo pack: Copper‐catalyzed trifluoromethylation of alkenes bearing an allylic proton combined with CCbondformation affords the title compounds in good to high yields (see scheme). The reactions are faster than allylic trifluoromethylation, especially in 1,4‐dioxane. A unique 1,6‐oxytrifluoromethylation occurred instead of an anticipated seven‐membered ring forming carbotrifluoromethylation