Bifunctionalized Allenes. VI. Synthesis of 3‐Sulfinylfuran‐2(5H)‐ones and 5H‐1,2‐Oxathiole‐3‐carboxylate 2‐Oxides by Bromination of 2‐Sulfinyl‐2,3‐alkadienoates
摘要:
3-Sulfinylfuran-2(5H)-ones 3 and 4 and 5H-1,2-oxathiole-3-carboxylate 2-oxides 5 were synthesized in very good yields via electrophile-induced cyclization reactions of 2-sulfinyl-2,3-alkadienoates 1 and 2. Bromination of ethyl 2-alkyl(phenyl)sulfinyl-2,3-alkadienoates 1 afforded 4-bromo-3-alkyl(phenyl)sulfinylfuran-2(5H)-ones 3 only, while the reaction with ethyl 2-alkoxysulfiiiyl-2,3-alkadienoates 2 led to formation of mixtures of 4-bromo-3-alkyloxysulfinylfuran-2(5H)-ones 4 and 4-bromo-5H-1,2-oxathiole-3-carboxylates 2-oxides 5.