Nucleophilic Addition to C, C‐Double Bonds. IV. Ether formation by intramolecular addition to unsymmetrically alkyl‐substituted C, C‐double bonds

Abstract

Abstract Tricyclic olefinic alcohols containing an unsymmetrically alkyl‐substituted C, C‐double bond were cyclized intramolecularly to their corresponding ethers under basic conditions: 9 → 12 , 10 → 17 + 18 , and 11 → 12 (Scheme 3, Table 1) . The reactivity is mainly due to relieve of ground state strain. Alcohol 9 (endocyclic double bond) isomerized under intramolecular assistance by the hydroxyl group to 11 (exocyclic double bond) before cyclization to 12 occurred (Scheme 5) . The latter step being the faster one, no isomerization 11 → 9 was observed.