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Nitron derivative, 8-hydroxy-1,4,5,7-tetramethyl-6,8-diazabicyclo [3.2.1]oct-6-ene 6-oxide, was obtained by the cyclodimerization of 3-methyl-3-buten-2-one oxime at 80 °C. This nitron was easily converted into the stable nitroxy radical by the attack of poly(N-methylacrylamide) radical.

The reported Robinson annelation of 2-methylcyclohexanone with 3-penten-2-one has been reexamined. In contrast to the previous result, it was found that the reaction product was not only obtained in a low yield, but also the solvent-depending stereoselectivity in the formation of cis-4,4a-dimethyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one (3a) and its trans isomer (3b) was considerably lower than that reported. As expected, regioisomers, 4β,8α-dimethyl-4,4aβ,5,6,7,8-hexahydronaphthalen-2(3H)-one and 4β,8β-dimethyl-4,4aα,5,6,7,8-hexahydronaphthalen-2(3H)-one, were also formed in the annelation. A similar tendency was observed in the reaction with 4-phenyl-3-penten-2-one. The annelation products, 3a, 3b, cis-4-phenyl-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one, and trans-4-phenyl-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2 (3H)-one, were also synthesized by an alternative route.

The synthesis of a new chelating reagent, l,l,l-trifluoro-4-(2-thienyl)-4-seleno-3-buten-2-one (SeTTA) by the reaction of hydrogen selenide in a stream of nitrogen gas with TTA in absolute ethanol in the presence of hydrogen chloride is described. The analytical application of SeTTA is also discussed.

The crystal and molecular structure of a hydroxy derivative of α-ionone, 4-(hydroxy-2,6,6-trimethyl-2-cyclohexenyl)-3-buten-2-one, was studied by means of X-ray analysis. The atoms including the conjugated double bond in the side chain and those around the double bond in the ring form planes orthogonal to each other.