Dibromodifluoromethane → 1,1-Difluoro-1,11-dodecadiene

Participants

Reaction Steps

Other primary and secondary alcohols of the present invention were also prepared from commercially available omega unsaturated alcohols by a second route. An unsaturated alcohol (I), e.g., 10-undecen-1-ol, was first oxidized to 10-undecen-1-al (V) by the Swern oxidation using oxalyl chloride, dimethyl sulfoxide, and triethylamine in methylene chloride. This aldehyde was then reacted with dibromodifluoromethane, triphenylphosphine, and powdered zinc in dimethylacetamide, producing 1,1-difluoro-1,11-dodecadiene (VI). In order to prepare a secondary alcohol from (VI), the latter was reacted with mercuric acetate in tetrahydrofuran and water and then with sodium borohydride and aqueous sodium hydroxide, producing 12,12-difluoro-11-dodecen-2-ol (VII). Oxidation of (VII) with Jones reagent in acetone yielded methyl 10,10-difluoro-9-decenyl ketone (VIII) which could in turn be reacted with a Grignard reagent, e.g., methylmagnesium bromide, to produce 2-methyl-12,12-difluoro-11-dodecen-2-ol (IX), a tertiary alcohol. Synthesis of primary alcohols was accomplished by reacting (VI) with borane tetrahydrofuran complex and then with sodium hydroxide and hydrogen peroxide, yielding 12,12-difluoro-11-dodecen-1-ol (X). Examples 3, 4, and 5 detail the methods employing this route.

Provenance & Evidence