Synthesis of 1, 4-Diketones by the Reaction of Alkyl Vinyl Ketones with Nitroalkanes Catalyzed by Tributylphosphine

Abstract

1, 4-Diketones, which are important intermediates for synthesis of jasmonoids and terpenoids, were prepared by the reaction of alkyl vinyl ketones with nitroalkanes catalyzed by tributylphosphine (TBP), followed by Nef reaction of the resulting nitroketones.
The Michael reaction of 3-butene-2-one to nitroethane was carried out by using a variety of tertiary phosphines as catalyst in benzene at room temperature, 2-nitro-5-heptanone being obtained in 86% yield by tributylphosphine catalyst. Nitroketones thus obtained in 6895% yield were subjected to the Nef reaction to give 1, 4-diketone derivatives.
The latter compounds were converted to dihydrojasmone, 5, 6-dimethyl-5-heptene-2-one and Karahanaenone, respectively.