THIOPHENOL ADDITIONS TO ALKENYLIDENECYCLOPROPANES. A NOVEL SYNTHESIS OF KARAHANAENONE

Article abstract of DOI:10.1016/S0040-4039(00)87118-X

The additions of thiophenol to alkenylidenecyclopropanes (e.g. 3, 14) are found to be highly regioselective and stereoselective leading to endo- (or cis-) vinyl sulphide adducts (e.g. 4, 15) resulting from additions to the 1,4-double bonds in the starting materials.Thiophenol addition to (1) leads to a mixture of the vinyl sulphides (16) and (17) which undergo Cope rearrangement producing the cycloheptadiene (18); hydrolysis of (18) then gives karahanaenone (19) an odoriferous constituent of Japanese hop and Cypress oil.