99304-45-7Relevant academic research and scientific papers
The Chemistry of Terpenes. Part 26. A Re-examination of the Neutral Products of the Oxidation of (-)-Fenchone, and (+)-2-endo-Fenchyl Acetate, and of the Bromination of (+)-Fenchone.
Cocker, Wesley,Gordon, Robert L.,Shannon, Patrick V. R.
, p. 2101 - 2147 (2007/10/02)
A re-examination of the products of oxidation of (-)-fenchone (1) with chromyl acetate in acetic acid has confirmed that (-)-fenchane-2,5-dione (2) and (+)-fenchane-2,6-dione (3) are the main products.Two other compounds have been isolated, namely (+)-(1R)-6-exo-acetoxy-3,3,6-trimethyltrinorbornan-2-one (4) and (+)-(1R,2S,6R)-2,8,8-trimethyl-3,5-dioxatricyclo2,6>decane-4,9-dione (5).Similar oxidation of (+)-2-endo-fenchyl acetate (6) yields (-)-(1S)-2-endo-acetoxy-1,3,3-trimethyltrinorbornan-5-one (7), (+)-(1R)-2-endo-acetoxy-1,3,3-trimethyltrinorbornan-6-one (8), (+)-(1S)-2-endo-5-exo-diacetoxy-1,3,3-trimethyltrinorbornane (9), (+)-(1R,5S)-7-endo-acetoxy-1,6,6-trimethyl-3-oxabicyclooctane-2,4-dione (10), and (-)-(1S,3S,7S,8R)-8,10,10-trimethyl-4,6-dioxatricyclo3,8>decane-2,5-dione (11).Derivatives of these compounds are described.Bromination of (+)-fenchone (12) in presence of copper gave (+)-(1R)-1-bromomethyl-3,3-dimethyltrinorbornan-2-one (13) as the major product, but a significant amount of (-)-(1R)-7-anti-bromo-1,3,3-trimethyltrinorbornan-2-one (14) was also formed.Minor amounts of (+)-(1R)-3-endo-bromo-1,7,7-trimethyltrinorbornan-2-one (15), and probably (g.l.c.) either 5-exo- or 6-exo-bromofenchone, were formed.Methanolysis of the anhydride (10) affords the half-ester (16) from which the β-lactone (17) is obtained.
