[摘要]：On irradiation (lambda = 350 nm) in the presence of 1,1-dimethoxyethene, naphthalene-1,2-dionemonoacetals 1 regioselectively afford 1,1,4,4-tetramethoxycyclobuta[a]naplithalen-3-ones 3. Sequential deprotection of these bis-acetals first lead to 1,1-dimethoxycyclobuta[a]naphthalene-3,4-diones 4 and then to cyclobuta [a] naphthalene-1,3,4-triones 6, which, in turn, are converted into (3,4-dihydro-3,4-dioxonaphthalen-2-yl)acetates 7 by treatment with SiO2/MeOH/air.
