Iron-Catalyzed Highly Regio- and Stereoselective Conjugate Addition of 2,3-Allenoates with Grignard Reagents
作者:Zhan Lu、Guobi Chai、Shengming Ma
DOI:10.1021/ja075750o
日期:2007.11.28
An efficient highly regio- and stereoselective iron-catalyzed conjugate addition of 2,3-allenoates with primary or secondary alkyl, phenyl, or vinyl Grignardreagents to synthesize multi-substituted β,γ-unsaturated enoates has been reported. The in situ formed magnesium dienolate may readily react with different electrophilic reagents to construct an allylic quaternary carbon at the α-position of the
Studies on electrophilic addition reaction of 2,3-allenoates with PhSeCl
作者:Guofei Chen、Chunling Fu、Shengming Ma
DOI:10.1016/j.tet.2006.02.053
日期:2006.5
butenolides were prepared from 2,3-allenoates and PhSeCl in the presence of water. The yields of the products depend largely on the structures of 2,3-allenoates. The addition of water is crucial for some of this electrophilic cyclization. The reaction of simple unsubstituted methyl 2,3-butadienoate afforded methyl 4-chloro-3-phenylselanylbut-2(Z)-enoate in good yield and stereoselectivity.
Electrophilic Interaction of 2,3-Allenoates with PhSeCl. An Unexpected Highly Stereoselective Synthesis of 3-Phenylseleno-4-oxo-2(<i>E</i>)-alkenoates
作者:Guofei Chen、Chunling Fu、Shengming Ma
DOI:10.1021/jo061680c
日期:2006.12.1
We have previously reported an efficient synthesis of beta-phenylselenium-substituted butenolides via electrophilic cyclization of 2,3-allenoates with PhSeCl in aqueous MeCN. However, when 2,3-allenoates were treated with PhSeCl in MeCN, 3-phenylseleno-4-oxo-2(E)-alkenoates were formed unexpectedly. The addition of Li2CO3 improved the yield and the selectivity of the reaction. A possible mechanism involving a decomposition of selenate esters was proposed.
Diversified assembly of perfluoroalkyl-substituted furans and 2,5-dihydrofuran-2-ols
作者:Guofei Chen、Guangke He、Can Xue、Chunling Fu、Shengming Ma
DOI:10.1016/j.tetlet.2010.10.085
日期:2011.1
We have developed a facile and effective synthesis of 3-iodofurans from 3-monosubstituted 1,2-allenyl perfluoroalkyl ketones or 2-hydroxy-4-iodo-2,5-dihydrofurans from 3,3-disubstituted 1,2-allenyl perfluoroalkyl ketones. The perfluoroalkyl substituent and the amount of water in the solvent are important for the success of this electrophilic cyclization. (C) 2010 Elsevier Ltd. All rights reserved.