The rearrangement of a diterpene epoxy ϵ-lactone system

✍ Scribed by C.W.J. Chang; S.W. Pelletier

• Publisher: Elsevier Science
• Year: 1966
• Tongue: French
• Weight: 215 KB
• Volume: 7
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)70127-4

✦ Synopsis

The oxidation of a,@unsatumted ketones with pemcids is known to yield enol and/or epoxy esters or lactones depending on the reaction conditions and on whether the enone is alicyclic or acyclic *. For example, we have found that treatment of methyl (+)-I 3-oxo-deisopropylideneneoabietate I (obtained frcm methyl (+)necabietate) with m_chloroperbenroic acid in methylene chloride, yields: (A) a crystalline mixture of the enol (-lactone II and the epoxy c-lactone Ill in a mtio of 35/65 or (B) compound III exclusively, depending upon conditions. Exclusive formation of ill resulted from refluxing I with an excess of m-chloroperbenzoic acid for 24 hours.