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

The synthesis of yomogi alcohol (2,5,5-trimethyIhepta-3,6-dien-2-01, 2) is described, and experiments directed towards its allylic rearrangement to artemisia alcohol derivatives have been carried out. Acidic reagents open thc ring of yomogi alcohol epoxide (16) and 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 rcagents are without effect when this double bond is reduced. Action of butyllithium on the benzaldehyde acetal (41) of 2,5-dimethyl-4-vinyl-2, 3dihydroxy-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 0-acetyy yomogi alcohol epoxide (46), from which a compound believed to be an oxetan 48 (R = COCH,) is formed with coneomitent shift of the acetate group. Further unusual reactions of the oxetan are described, and some observations about the epoxiclation of sterically hindered ally1 alcohols and their acetates are made. l) 2,Ce travail a fait I'objet d'une Communication priliminaire [l]. Pour la premiiire publication de cette sirie voir [2].

Biogenetic-Type Rearrangements of Terpenes

“…lt has been possible to effect the reverse rearrangement, i. e., the con-· version of artemisyl derivations to chrysanthemane andjor santalinane products (71,72), as shown below. These homoallyl ~ homoallyl rearrangements no doubt proceed through a cyclopropylcarbinyl (chrysanthemyl) intermediate [e.g., (29-+28-+31)].…”