Synthesis and Reactions of Monosilylated 1,3,5-Hexatriyne and 1,3,5,7-Octatetrayne. Total Synthesis of Caryoynencins

Selective monodesilylation of 1,8-bis(t-butyldiphenylsilyl)-1,3,5,7-octatetrayne and 1,6-bis(t-butyldiphenylsilyl)-1,3,5-hexatriyne with lithiated phenylacetylene gave unstable 1-(t-butyldiphenylsilyl)-1,3,5,7-octatetrayne and 1-(t-butyldiphenylsilyl)-1,3,5-hexatriyne, respectively. The terminal acetylenes on lithiation added to aldehydes and a ketone giving polyynols in high yields. The reaction was applied to the synthesis of polyyne antibiotics, caryoynencins. Polymerization of the terminal octatetrayne on an ITO-coated glass plate gave a film, which showed conductivity of 10−4 S cm−1 when doped with SO3.