

OPENING OF THE FURAN RING OF 3-NITROBENZOFURANS BY THE ACTION OF CARBONYL-STABILIZED SULFONIUM YLIDES

Abstract
Upon treatment of 3-nitrobenzofurans with dimethylphenacylsulfonium salts in the presence of a base, the opening of the furan ring to form (E)-1-aryl-2-(dimethylsulfonio)-4-nitro-1-oxobut-3-en-2-ides takes place. The mechanism of nucleophilic dearomatization of 3-nitrobenzofurans involves consecutive carbo- and retro-oxa-Michael reactions. The reaction illustrates the high propensity of 3-nitrobenzofurans for ring opening.
Keywords
dimethylphenacylsulfonium salts; 3-nitrobenzofurans; sulfur ylides; Michael reaction; nucleophilic dearomatization.
Latvian Institute of Organic Synthesis - Aizkraukles iela, 21, Riga, LV-1006, Latvia - hgs@osi.lv