Nitroalkanes as nucleophiles in a self-catalytic Michael reaction
A simple, effective procedure for the preparation of 4-nitroalkanoates 6–9 by the Michael reaction of nitroalkanes 2–5 with the acrylate 1 is described. The primary nitro adduct 6 undergoes isomerization to hydroxamic acid 10 while heated in boiling nitromethane. Consecutive reactions of the latter compound lead to the formation of N-hydroxysuccinimide 11 and its N-ethoxy derivative 12. The spontaneous Nef reaction of the mother 4-nitrobutanoic acid 15 gives N-hydroxysuccinimide 14. The analogous reaction of secondary nitroalkanoic acids 16 and 17 provides 4-oxoalkanoic acids 18 and 19, respectively. Intramolecular participation by the carboxylic acid group in the Nef reaction is proposed.