A NOVEL SYNTHESIS OF l-CARVONE FROM l-α-PINENE

Abstract

A novel synthetic method of l-carvone involving the anodic oxidation of the enol acetate of isopinocamphone in the mixed solvent of methylene chloride-acetic acid as a key step was established. The overall yield of l-carvone from l-α-pinene was 34% and the overall optical yield was quantitative.

The pinene scaffold: its occurrence, chemistry, synthetic utility, and pharmacological importance

“…Carvone can be prepared from pinene through anodic oxidation of pinene enol acetate (43) derived from oxidative hydroboration of a-pinene with H 2 O 2 and CrO 3 in the presence of enol acetate (Scheme 13) as demonstrated by Shono 45 and his group. In Shono's anodic oxidation of pinene enol acetate (43), carvone (44) was obtained in 64% yield when 8 : 1 DCM-AcOH and tetraethylammonium p-toluenesulfonate (Et 4 NOTs) were used.…”

Some Progress and Development on Synthetic Electroorganic Chemistry

“…Furthermore, it was found that anodic oxidation of enol acetates in anodic oxidation containing Et 4 NOTs and Et 3 N led to α,β-unsaturated enones 5) and α-acetoxy ketones 6) , respectively, in good yields. These methods were applied to novel synthesis of useful natural products, such as jasmonate 5) , ι-carvone 7) , and 1,2-carbonyl transposition.…”

“…These methods were applied to novel synthesis of useful natural products, such as jasmonate 5) , ι-carvone 7) , and 1,2-carbonyl transposition. 6) It may be interesting that abnormal rearrangement to the corresponding lactones 8) efficient direct hydroxylation was accomplished through electroreduction of of cyclic ketones and benzene derivatives, especially halogenated benzenes and alkyl benzoates, resectively, in CF 3 COOH-Et 3 N, followed by hydrolysis on work-up.…”