H. Detert et al., PREPARATION OF 1,5-CYCLOOCTADIYNE AND 1,3 ,5,7-CYCLOOCTATETRAENE FROM1,5-CYCLOOCTADIENE, Chemische Berichte, 127(8), 1994, pp. 1529-1532
Bromination of 1,5-cyclooctadiene (1) and stepwise dehydrobromination
first with KOtBu and then with KOtBu/18-crown-6 yields 1,5-cyclooctadi
yne (5). A prolonged interaction of the base causes a complete transfo
rmation to cyclooctatetraene (6). Diyne 5 and even more the intermedia
te enyne 4 are highly reactive dienophiles. The cycloadducts 10-14 for
med with 1,3-cyclohexadiene, carbon disulfide, and tetraphenylcyclopen
tadienone were isolated and characterized. Treatment of 5 with titaniu
m tetrachloride induces a vigorous polymerization.