Addition of Alkyl Vinyl Ketone to Aldehydes Catalyzed by Tertiary Phosphine

Abstract

Addition of alkyl vinyl ketones [1] to aldehydes [2]in the presence of tertiary phosphine as a catalyst was studied. In the reaction of 1-penten-3-one [1a] with isobutyraldehyde [2d] catalyzed by triphenylphosphine, 5-hydroxy-4-methylene-6-methyl-3-heptanone [3d], an aldol-type adduct, was obtained. The reaction of [1a] with various aldehydes [2a-g]gave 5-alkyl-5-hydroxy-4-methylene-3-pentanone [3a-g] in 55-80% yield. In the reaction of various alkyl vinyl ketone [1b-f] with [2], aldol-type adducts [3h-1] were obtained in good yields. The reaction of [1] with α, α-dialkylacetaldehydes [2] catalyzed by tributylphosphine yielded Michael-type adducts C5[5a-e]. The reactions were considered to proceed through phosphonium betaine intermediates which attack the aldehydes as in the aldol or Michael-type addition.