Chemistry of o-Benzoquinones and Masked o-Benzoquinones. VI. Cycloaddition of 6, 9 Dipropyl-1, 4-Dioxaspiro[4.5] Deca-6, 8-Dien-2, 10-Dione with Cycloheptatriene

Cycloaddition of masked o-benzoquinone, 6,9-dipropyl-1, 4-dioxaspiro4.5]deca-6, 8-dien-2,10-dione, with cycloheptatriene afforded mainly 4π+2π] adducts which was transformed into 1, 4-dipropyl-5H-benzocycloheptene by hydrolysis, photolysis and dehydrogenation consecutively. These reaction sequences represent a novel method for the synthesis of 5H-benzocycloheptene from catechol via masked o-benzoquinone.