Natural acetylenes. Part 53. A route to C5, C6, and C7cis- and trans-alk-3-en-1-ynes via their trimethylsilyl derivatives

cis- and trans-1-Trimethylsilyl-pent-3-en-1-yne, -hex-3-en-1-yne, and -hept-3-en-1-yne have been prepared by fractional distillation of their cis–trans-mixtures and shown to provide a convenient route for the synthesis of the corresponding stereoisomeric terminal acetylenes.