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.
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.