Electrophilic interaction of 2,3-allenoates with PhSeCl. An unexpected highly stereoselective synthesis of 3-phenylseleno-4-oxo-2(E)-alkenoates.
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.
Chen
Guofei
G
Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, PR China.
Fu
Chunling
C
Ma
Shengming
S