Alkoxycarbonyl-substituted 3-trifloxypropene iminium salts and iminium-substituted Delta(2,3)-butenolides: Synthesis and reactivity toward nucleophiles

摘要

Triflic anhydride reacts regioselectively with the ethoxycarbonyl-substituted enaminones 6a-h to give the novel 3-trifloxypropene iminium salts 7a-d or iminium-substituted Delta(2,3)-butenolides 8a-d and 9a-d in good yields. Hydride reduction of the iminium salts 7a,b affords new 2-dialkylamino-4-trifloxy-but-3-enoates 13a,b, while mild hydrolysis generates 2-oxo-4-trifloxybutenoates 14a,b. Butenolides 8b,d, and 9c react with methyl hydrazine to afford 4-dialkylamino-pyridazin-3(2H)-ones 12a-c. [References: 22]