trans-Cycloalkenes. Part 11. trans-Cyclonona-1,2,6-triene, a transient precursor of 2,3-divinylcyclopentene

Abstract

Three potential precursors of trans-cyclonona-1,2,6-triene (1), namely the allene-dioxolan (7), the allene-oxathiolan (14), and the dichlorocyclopropane (16) have been prepared starting ultimately from cyclo-octa-1,5-diene. Treatment of these precursors with BuⁿLi under conditions appropriate to each case gave 2,3-divinylcyclopentene in moderate to good yields. It is considered that trans-cyclonona-1,2,6-triene is formed as a transient intermediate.