The morpholino enamine of monoprotected butane-2,3-dione reacts with c
yclic and acyclic conjugated nitroalkenes in a Michael-type reaction t
o yield nitro-substituted alpha-diketones, after acidic hydrolysis of
the mononitroalkylated enamine adducts. Cyclopentanone, hexahydro-1H-p
entalen-2-one and octahydro-2H-inden-2-one derivatives are readily obt
ained by base-catalyzed intramolecular nitroaldol reaction of the acyc
lic hydrolysis products.