Camphor and Isocamphanone in the Synthesis of Disubstituted Acetylene Alcohols, Ethers, and Esters

Abstract

By treating 1-octyne and phenylacetylene with butyllithium the corresponding lithium acetylides were obtained that with camphor and isocamphanone provided along streospecific process 2-exo-(1-octynyl or 2-phenyl-1-ethynyl)-2-endo-lithiumoxy-5,5,6-trimethylbicyclo[2.2.1]heptane and 2-endo-(1-octynyl or 2-phenyl-1-ethynyl)-2-exo-lithiumoxy-1,7,7-trimethylbicyclo[2.2.1]heptane. The hydrolysis of these lithium alcoholates occurred selectively and resulted in individual tertiary terpene alcohols containing exo-acetylene substituent in the case of camphor, endo-acetylene fragment in the case of isocamphanone. The alcohols reacted with methyl, ethyl, or butyl iodides in the presence of hexamethylphosphoramide to afford ethers, and with benzoyl chloride to furnish disubstituted esters of benzoic acid.