反应详情

A 3', 4'-dihydrospiro[cyclohexane-1,2'(1'H)-naphthalene]-4', 4-dione (6) obtained in step (6) is monoketalized at the non-conjugated least hindered carbonyl function, e.g., by heating (at reflux) in a solvent such as benzene with an alkylene glycol (in the presence of a catalyst such as p-toluenesulfonic acid), to yield a corresponding 3', 4', -dihydrospiro[cyclohexane-1,2'(1'H)-naphthalene]-4',4 -dione, 4-(ethylene ketal) (7).

1. temperatureby heating