49815-62-5Relevant academic research and scientific papers
172. β-Cleavage of Bis(homoallylic) Potassium Alkoxides. Two-Step Preparation of Propenyl Ketones from Carboxylic Esters. Synthesis of ar-Turmerone, α-Damascone, β-Damascone, and β-Damascenone
Snowden, Roger L.,Linder, Simon M.,Muller, Bernard L.,Schulte, Karl H.
, p. 1858 - 1878 (2007/10/02)
The transformation of 36 bis(homoallylic) alcohols VII to alkenones IX and X via β-cleavage of their potassium alkoxides VIIa in HMPA has been investigated (cf.Scheme 2).These studies have established an order of β-cleavage for 2-propenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 1,1-dimethyl-2-propenyl, and benzyl groups in alkoxides 49a-56a and have allowed a comparison between the β-cleavage reaction and the oxy-Cope rearrangement in alkoxides 74a-83a.As illustrative synthetic applications, a two-step preparation of propenyl ketones 15-42 from carboxylic esters is described, together with syntheses of ar-turmerone (48), α-damascone ((E)-71), β-damascone ((E)-109), and β-damascenone ((E)-111).
GRIGNARD AND HYDRIDE ADDITION TO A KETENE INTERMEDIATE: A NOVEL ACCESS TO α-DAMASCONE AND α-CYCLOCITRAL
Naef, Ferdinand,Decorzant, Rene
, p. 3245 - 3250 (2007/10/02)
α-Damascone (1), a rose fragrance chemical, was synthesized by an allylmagnesium chloride addition to ketene 7 as key step.When the same ketene 7 was reduced by two different aluminium hydride reagents, α-cyclocitral was obtained.The presumed intermediates, enolates II and III, were first trapped as silyl enol ethers and then hydrolyzed with D2O to give the expected α-monodeuterated carbonyl compounds.Mixed aluminium hydride reduction of ketenes is recommended as a facile entry into the chemistry of aldehyde enolates.
FRAGMENTATION OF HOMOALLYLIC ALKOXIDES. SYNTHESIS OF PROPENYL and 2-METHYLPROPENYL KETONES FROM CARBOXYLIC ESTERS
Snowden, Roger L.,Muller, Bernard L.,Schulte-Elte, Karl H.
, p. 335 - 338 (2007/10/02)
An efficient two-step synthesis of propenyl and 2-methylpropenyl ketones from carboxylic esters is described which uses as the key step the fragmentation of a potassium dihomoallylic alkoxide under mild thermolytic conditions.
