An Efficient Approach for Monofluorination via Highly Regioselective Fluorohydroxylation Reaction of 3-Aryl-1,2-allenes with Selectfluor
摘要:
The internal C-C double bond in 3-aryl-1,2-allenes was highly regioselectively fluorohydroxylated to afford 2-fluoroalken-3-ols in 37-88% yields by using Selectfluor as the electrophilic reagent. The regioselectivity may be determined by the electronic effect, while the reactivity may be controlled by the stabilization effect of the aryl group in the allylic cationic intermediates.
An Efficient Approach to 2-Bromoalken-3-ols by Regioselective Bromohydroxylation Reaction of Simple Allenes with NBS
作者:Wangqing Kong、Binjie Guo、Chunling Fu、Shengming Ma
DOI:10.1002/ejoc.201001676
日期:2011.4
A regioselectivebromohydroxylationreaction of simpleallenes affording 2-bromoalken-3-ols in moderate-to-good yields has been developed by using NBS as the electrophilic reagent in a mixture of 1,4-dioxane/H 2 O (1:1) at room temperature. Through this study it has been concluded that the regioselectivity is determined by various factors including steric and electronic effects of the substituents
通过在 1,4-二恶烷/H 2 O (1:1) 混合物中使用 NBS 作为亲电试剂,开发了简单丙二烯的区域选择性溴羟基化反应,以中等至良好的收率提供 2-bromoalken-3-ols在室温下。通过这项研究得出的结论是,区域选择性由各种因素决定,包括丙二烯部分取代基的空间和电子效应。
Studies on Cu(I)-catalyzed synthesis of simple 3-substituted 1,2-allenes and optically active 2-substituted secondary 2,3-allenols
作者:Jing Li、Chao Zhou、Chunling Fu、Shengming Ma
DOI:10.1016/j.tet.2009.02.061
日期:2009.5
methyl ethers, which would react with primary alkyl Grignard reagents under the catalysis of CuBr to afford 3-substituted 1,2-allenes or 2-substituted secondary 2,3-allenols, respectively. The reaction may be applied to the synthesis of optically active 2-substituted secondary 2,3-allenols with up to >99% ee without any protection to the free hydroxyl group in the starting 4-hydroxy-2-alkynyl methyl
Catalytic enantioselective allene–anhydride approach to β,γ-unsaturated enones bearing an α-all-carbon-quarternary center
作者:Yuan Yuan、Xue Zhang、Hui Qian、Shengming Ma
DOI:10.1039/d0sc03227a
日期:——
A protocol of highly regio- and enantioselective copper-catalyzed hydroacylation of the non-terminal CC bond in 1,1-disubstituted terminal allenes with anhydrides has been developed. Both aromatic and aliphatic carboxylic anhydrides are applicable to the efficient construction of all carbon quarternary centers connected with a versatile CC bond and a useful ketone functionality. The synthetic potentials
Carbocupration/Zinc Carbenoid Homologation and β-Elimination Reactions for a New Synthesis of Allenes − Application to the Enantioselective Synthesis of Chiral Allenes by Deracemization of sp3-Organometallic Derivatives
作者:Jos P. Varghese、Irena Zouev、Lionel Aufauvre、Paul Knochel、Ilan Marek
straightforward carbocupration/zinc homologation/β-elimination reaction sequence allows the one-pot synthesis of polysubstituted allenes from acetylenic sulfoxides in excellent isolated chemical yields. Secondary zinccarbenoids were used for the homologation reaction, and so a new synthesis of 1,1-diiodoalkanes is described. This methodology also allows the synthesis of chiral allenes through thermodynamic
Intermolecular Mn(OAc)<sub>3</sub>-Mediated Oxidative Free-Radical Reaction of Dimethyl Malonate or Ethyl Cyanoacetate with Allenes: An Efficient Synthesis of Furan-2(5<i>H</i>)-ones or Dimethyl 2-(2-Oxoethylidene)malonates
作者:Xian Huang、Zhimeng Wu
DOI:10.1055/s-2006-958925
日期:2007.1
Manganese(III)-mediated free-radical reaction of allenes with dimethyl malonate or ethylcyanoacetate in acetic acid produces furan-2-(5//)-one derivatives (but-2-en-4-olides) or dimethyl 2-(2-oxoethylidene)malonates in moderate yields. The possible reaction mechanism is also discussed.