Iron-Catalyzed, Site-Selective Difluoromethylthiolation (−SCF<sub>2</sub>H) and Difluoromethylselenation (−SeCF<sub>2</sub>H) of Unactivated C(sp<sup>3</sup>)–H Bonds in <i>N</i>-Fluoroamides
作者:Hongwei Zhang、Fei Yu、Chuang Li、Peiyuan Tian、Yulu Zhou、Zhong-Yan Cao
DOI:10.1021/acs.orglett.1c01443
日期:2021.6.18
The iron-catalyzed δ-C(sp3)–H bond difluoromethylthiolation and difluoromethylselenation of aliphatic amides with high site selectivity are reported. Essential to the success is the employment of an amide radical formed in situ to activate the inert C(sp3)–H bond and the utilization of the easily handled PhSO2SCF2H and PhSO2SeCF2H as coupling reagents under mild conditions. This scalable protocol exhibits
报道了铁催化的 δ-C(sp 3 )-H 键二氟甲硫基化和脂肪族酰胺的二氟甲基硒化,具有高位点选择性。成功的关键是使用原位形成的酰胺自由基来激活惰性 C(sp 3 )-H 键,并在温和条件下使用易于处理的 PhSO 2 SCF 2 H 和 PhSO 2 SeCF 2 H 作为偶联剂. 这种可扩展的协议展示了具有多功能功能组的广泛基板范围。机理研究表明,反应通过-SCF 2 H 和-SeCF 2 H 自由基转移进行。
Copper‐Catalyzed Remote Direct Thiocyanation of Alkyl C(
<i>sp</i>
<sup>3</sup>
)−H Bonds
A method for site‐selective intermolecular C(sp3)−Hthiocyanation of aliphatic sulfonamides is developed using cheap trimethylsilyl isothiocyanate (TMSNCS) as the thiocyanation reagent, catalyzed by simple Cu(I)/phenanthroline complex. The mild, and modular protocol allows remoteC(sp3)−Hthiocyanation in promising yields with a broad substrate scope.
Sulfonamide-Directed Chemo- and Site-Selective Oxidative Halogenation/Amination Using Halogenating Reagents Generated in Situ from Cyclic Diacyl Peroxides
作者:Denghu Chang、Rong Zhao、Congyin Wei、Yuan Yao、Yang Liu、Lei Shi
DOI:10.1021/acs.joc.8b00243
日期:2018.3.16
The combination of cyclicdiacylperoxides with commercially available halide salts as a unique halogenating system is utilized in Hofmann–Löffler–Freytag-type reaction. This strategy allows for the formation of N-chloroamides, δ-brominated products, and even biologically relevant pyrrolidines under mild conditions in moderate to excellent yields. Meanwhile, the preliminary structure of the in situ
Triiodide-Mediated δ-Amination of Secondary C−H Bonds
作者:Ethan A. Wappes、Stacy C. Fosu、Trevor C. Chopko、David A. Nagib
DOI:10.1002/anie.201604704
日期:2016.8.16
amination of unactivated, secondary C−Hbonds to form a broad range of functionalized pyrrolidines has been developed by a triiodide (I3−)‐mediated strategy. By in situ 1) oxidation of sodium iodide and 2) sequestration of the transiently generated iodine (I2) as I3−, this approach precludes undesired I2‐mediated decomposition which can otherwise limit synthetic utility to only weak C(sp3)−H bonds. The mechanism
site-selective δ-C(sp3)-Hbondsactivation of aliphatic sulfonamides for constructing the synthetically useful seven-membered N-heterocycles. A key to success is the use of in-situ-formed amide radicals, to activate the inert C(sp3)-H bond, and inexpensive TMSNCO, as a coupling reagent under mild conditions. To the best of our knowledge, this represents the first use of alkylamine derivatives as a five-membered