1,3-Dipolar Cycloadditions of 3-Bromo-1,5- and 3-Bromo-1,7-Azulenequinones with Diazomethane, Diphenylnitrilimine, And Benzonitrile Oxide

摘要

The reactions of 3-bromo-1,5-and 3-bromo-1,7-azulenequinones wiht diazomethane gave cycloctatrienone derivatives and a [4+2] 1,3-dipolar adduct while they reacted with diphenylnitrilimine and benzonitrile oxide to give the corresponding [4+2] 1,3-dipolar adducts, showing the different site selectivities. 3-Bromo-1,5-azulenequinone reacted with the 1,3-dipoles dominantly to form the adducts on the cyclopentenone part while 3-bromo-1,7-azulenequinone reacted on the seven-membered ring.