The Synthesis and Reactions of Yomogi Alcohol. Conversion of the artemisyl skeleton to the santolinyl skeleton by a 1,2‐shift of a vinyl group. Synthesis of santolinatriene

Abstract

AbstractThe synthesis of yomogi alcohol (2, 5, 5‐trimethylhepta‐3,6‐dien‐2‐ol, 2) is described, and experiments directed towards its allylic rearrangement to artemisia alcohol detervatives have been carried out. Acidic reagents open the ring of yomogi alcohol epoxide (16) at with participation of the 6,7‐double‐bond, a shift of the vinyl group results to yield a compound with the santolinyl skeleton. The same reagents are without effect when this double bond reduced. Action of butyllithium of the benzaldehyde acetal (41) of 2, 5‐dimethyl‐4‐vinyl‐2, dihydroxy‐hex‐5‐ene (28), obtained by acid‐catalyzed ring opening of yomogi alcohol epoxide in the presence of benzaldehyde, leads to santolinatriene (42).This vinyl shift is not observed in the case of O‐acetyl yomogi alcohol epoxide (46), from white a compound believed to be an oxetan 48 (R  COCH3) is formed with concomitent shift of the acetate group. Further unusual reactions of the oxetan are described, and some observation about the epoxidation of sterically hindered allyl alcohols and their acetates are made.