Cycloadditions. 44. A two-step conversion of carbonyl compounds into functionalized five- and six-membered ring thioethers via intramolecular cycloaddition
Iridium-catalyzed highly chemoselective and efficient reduction of nitroalkenes to nitroalkanes in water
作者:Dong Xu、Yang Chen、Changmeng Liu、Jiaxi Xu、Zhanhui Yang
DOI:10.1039/d1gc01907d
日期:——
An iridium-catalyzed highly chemoselective and efficient transfer hydrogenation reduction of structurally diverse nitroalkenes was realized at very low catalyst loading (S/C = up to 10000 or 20 000), using formic acid or sodium formate as a traceless hydride donor in water. Excellent functionality tolerance is also observed. The turnover number and turnover frequency of the catalyst reach as high as
在非常低的催化剂负载量(S/C = 高达 10000 或 20 000)下,使用甲酸或甲酸钠作为水中的无痕氢化物供体,实现了铱催化的高化学选择性和高效转移氢化还原结构多样的硝基烯烃。还观察到优异的功能耐受性。催化剂的周转次数和周转频率高达18 600和19 200 h -1, 分别。不需要惰性气氛保护。硝基烯烃的反应性取决于它们的取代模式,pH 值是实现完全转化和优异化学选择性的关键因素。产品的纯化通过简单的萃取实现,无需柱层析。还原过程在 10 000 S/C 比率下轻松放大到 10 g 规模。这种绿色还原在对映选择性氢化中的潜力已经得到证实。
Chemoselective synthesis of multifunctional ferrocene-containing derivatives by the cross Rauhut–Currier reaction
作者:Dragana Stevanović、Jovana Bugarinović、Marko Pešić、Anka Todosijević、Goran A. Bogdanović、Ivan Damljanović
DOI:10.1039/d1ra07619a
日期:——
A simple protocol has been developed for the chemoselective synthesis of ferrocene-containing Rauhut-Currier adducts from 1-ferrocenyl-2-nitroethene and vinyl ketones using 20 mol% of triphenylphosphine. Multifunctional ferrocene derivatives were obtained in moderate to high yields (51-92%) by the couplingbetween the α-position of vinyl ketones and the β-position of the nitroalkene. The study of the
Bifunctional Squaramide-Catalyzed One-Pot Sequential Michael Addition/Dearomative Bromination: Convenient Access to Optically Active Brominated Pyrazol-5(4<i>H</i>)-ones with Adjacent Quaternary and Tertiary Stereocenters
organocatalytic asymmetric, one-pot, sequential Michael addition/dearomative bromination reaction of pyrazol-5-ones to nitro olefins and N-bromosuccinimide (NBS) has been developed. Under the catalysis of a chiral bifunctional squaramide, a wide variety of chiral brominated pyrazol-5-one derivatives with contiguous quaternary and tertiarystereocenters was obtained in high yields (up to >99 %) with good
Homologation of arylaldehydes provides useful synthetic intermediates, but it requires multistep reactions and generates significant amounts of waste. We considered such reactions using nitromethane as a C1 source through nitroolefin formation, partial hydrogenation to oximes, and hydration of oximes; however, the control of selectivity in the second reaction is challenging. To achieve this pathway