NHC/Nickel(II)‐Catalyzed [3+2] Cross‐Dimerization of Unactivated Olefins and Methylenecyclopropanes
作者:Jian‐Qiang Huang、Chun‐Yu Ho
DOI:10.1002/anie.201914542
日期:2020.3.23
typical hydroalkenylation reactivity was observed for the first time by using a [NHC-Ni(allyl)]BArF catalyst (NHC=N-heterocyclic carbene). Results show that the C-C cleavage of 1 did not involve a Ni0 oxidative addition, which was crucial in former systems. Thus the method reported here emerges as a complementary method for attaining highly chemo- and regioselectivesynthesis of methylenecyclopentanes
The reagent Et2AlX/CH2N2 in cyclopropanation of sterically hindered olefins, as well as oxygen- and nitrogen-containing unsaturated compounds
作者:I. R. Ramazanov、A. V. Yaroslavova、N. R. Yaubasarov、E. N. Gil’manova、U. M. Dzhemilev
DOI:10.1007/s11172-019-2638-5
日期:2019.10
A transition-metal-free method of cyclopropanation of sterically hindered olefins, substituted allylic alcohols, allylamines, and vinyl silyl ethers was developed using diazomethane in the presence of organic aluminum halides.
Synthesis of Spiro[2.2]pentanes and Spiro[2.3]hexanes Employing the Me<sub>3</sub>
Al/CH<sub>2</sub>
I<sub>2</sub>
Reagent
作者:Ilfir R. Ramazanov、Rita N. Kadikova、Tat'yana P. Zosim、Usein M. Dzhemilev、Armin de Meijere
DOI:10.1002/ejoc.201700991
日期:2017.12.22
Substituted alkylidenecyclopropanes reacted with 5 equivalents each of Me3Al and CH2I2 at room temperature in hexane to give 1-mono- and 1,1-disubstituted spiro[2.2]pentanes in high yields. Surprisingly, the same reaction with substituted alkylidenecyclopropanes in CH2Cl2 afforded exclusively 1,1-disubstituted spiro[2.3]hexanes. The transformation of 1,1-diphenylspiro[2.2]pentane into 1,1-diphenylspiro[2
Synthesis of Fluorinated Homoallylic Compounds by Fluoroalkyl Radical Mediated Ring Opening of Methylenecyclopropanes
作者:Huajun Xie、Bo Xu
DOI:10.1002/ejoc.201600380
日期:2016.5
The fluoroalkyl (Rf) radical mediated ringopening of methylenecyclopropanes (MCPs) 1 and subsequent atom transfer were investigated. In the first part, a copper-initiated radical reaction of Rf–X (X = I, Br) with MCP 1 gave homoallylic halides 2 in excellent yields. Similarly, radical reaction of the RfTMS/CsF/PhI(OCOR)2 system with MCP 1 led to homoallylic alcohol esters 3 in moderate to good yields
Bromine Radical-Mediated Sequential Radical Rearrangement and Addition Reaction of Alkylidenecyclopropanes
作者:Takashi Kippo、Kanako Hamaoka、Ilhyong Ryu
DOI:10.1021/ja311821h
日期:2013.1.16
Bromine radical-mediated cyclopropylcarbinyl-homoallyl rearrangement of alkylidenecyclopropanes was effectively accomplished by C-C bond formation with allylic bromides, which led to the syntheses of 2-bromo-1,6-dienes. A three-component coupling reaction comprising alkylidenecyclopropanes, allylic bromides, and carbon monoxide also proceeded well to give 2-bromo-1,7-dien-5-ones in good yield.
溴自由基介导的亚烷基环丙烷的环丙基羰基-高烯丙基重排通过与烯丙基溴形成 CC 键有效地完成,从而合成 2-溴-1,6-二烯。包括亚烷基环丙烷、烯丙基溴和一氧化碳的三组分偶联反应也进行得很好,以良好的收率得到2-溴-1,7-二烯-5-酮。