Synthesis of α-nitro carbonyls via nitrations in flow

Reported is a safe, rapid method for the synthesis of α-nitro esters, via the trapping of nitronium ions. The two-stage nitration and subsequent deacetylation of readily available 1,3-dicarbonyl compounds was achieved using a biphasic semi-continuous approach. α-Nitro esters and amides were obtained in good overall yields (53–84%). Some of the α-nitro-1,3-dicarbonyl intermediates exhibit enhanced reactivity and undergo an acid-catalyzed Nef-type reaction to α-oxo-carbonyls