In order to investigate the reactivity of naphtho[b]cyclopropene (2),
the reaction with various diencphiles, dienes and electrophiles was ex
amined. Reaction of 2 with tetracyanoethylene, 4-phenyl-3H-1,2,4-triaz
ole-3,5(4H)-dione, 1,3-diphenylisobenzofuran and benzyne afforded the
insertion products 3, 4, 6, 10. Cheletropic addition of dichlorocarben
e to 2 gave 1,1-dichloronaphtho[b]cyclobutene (II). Hydrolysis and red
uctive elimination of 12 provided naphtho[b]cyclobutenone (13) and nap
htho[b]cyclobutene (13), respectively. Naphtho[b]cyclopropene reacted
with the different electrophiles like acetic acid, HCl, maleic acid, i
odine, bromine, ethanol, and hydrogen afforded the corresponding ring-
opening products 14, 15, 16, 17, 18, 19, 20 and 21, respectively.