Macrocycles by Olefination of Dialdehydes with 1,3-Bis(dimethylphosphono)-2-propanone

Conjugated cyclic divinyl ketones containing fifteen and seventeen membered rings have been prepared in a single step by condensation of 1,3-bis (dimethylphosphono)-2-propanone ( 10 ) with the dialdehydes 14 , 17 , 20 , and 42 in the presence of hydrogencarbonate in aqueous t-butyl alcohol at reflux without using high dilution techniques. The more highly unsaturated aldehydes give better yields and ketones 34 and 36 , or mixtures of the two, were transformed to muscone ( 1 ) and Exaltone® by standard procedures. Civetone ( 2 ) was prepared by hydrogenation of 43 in pyridine solution. Dienone 29 appears to be the first α, β-unsaturated ketone in which one of the β-vinyl proton resonates at higher field than the corresponding α-proton.