Cycloadditions. 44. A two-step conversion of carbonyl compounds into functionalized five- and six-membered ring thioethers via intramolecular cycloaddition
unexplored area for C−C bond formation. Herein 64 examples of β‐alkylated styrene derivatives, synthesized through the reactions of readily accessible feedstock olefins with β‐nitrostyrenes by ozone/FeII‐mediated radical substitutions, are reported. These reactions proceed with good efficiencies and high stereoselectivities under mild reaction conditions and tolerate an array of functional groups. Also demonstrated
烯烃C(sp 3)-C(sp 2)键的脱烯基烯基化作用一直是C-C键形成的未知区域。本文报道了64个β-烷基化苯乙烯衍生物的例子,这些例子是通过容易获得的原料烯烃与β-硝基苯乙烯通过臭氧/ Fe II介导的自由基取代反应而合成的。在温和的反应条件下,这些反应具有良好的效率和较高的立体选择性,并且可以耐受一系列官能团。还证明了该策略通过产品的几种合成转化以及天然产物异吗啡丁和药物(E)-美丹尼丁的合成的适用性。
Chiral Squaramide-Functionalized Imidazolium-Based Organic–Inorganic Hybrid Silica Promotes Asymmetric Michael Addition of 1,3-Dicarbonyls to Nitroalkenes in Brine
作者:Xiangming Xu、Tanyu Cheng、Xiaochen Liu、Jianyou Xu、Ronghua Jin、Guohua Liu
DOI:10.1021/cs5002459
日期:2014.7.3
cinchona-based squaramide active center is incorporated onto the organic–inorganic hybrid silica. As a bifunctional heterogeneous catalyst, it displays excellent catalytic activity and high enantioselectivity in asymmetric Michael addition of 1,3-dicarbonyl compounds to nitroalkenes in brine. As presented in this study, the synergistic effect of confined site-isolated squaramide species and a salient imidazolium
Synthesis of Highly Substituted Phenols and Benzenes with Complete Regiochemical Control
作者:Xiaojie Zhang、Christopher M. Beaudry
DOI:10.1021/acs.orglett.0c02157
日期:2020.8.7
Substitutedphenols are requisite molecules for human health, agriculture, and diverse synthetic materials. We report a chemical synthesis of phenols, including penta-substituted phenols, that accommodates programmable substitution at any position. This method uses a one-step conversion of readily available hydroxypyrone and nitroalkene starting materials to give phenols with complete regiochemical
Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins
作者:Zheng Li、Geyang Song、Jiaojiao He、Yan Du、Jingya Yang
DOI:10.1080/17415993.2017.1369541
日期:2017.11.2
ABSTRACT Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins is described. A series of 2-((2-nitro-1-arylethyl)thio)pyrimidines were efficiently synthesized. The protocol has advantages of wide range of substituents tolerance, no catalyst, additives and bases, mild condition, and high yield. The method can also extend to gram scale. GRAPHICAL ABSTRACT