Furan Derivatives. IV. On the Effects of Substituents in the Syntheses of 4,5-Dihydro-3H-naphthofurans

Article abstract of DOI:10.1246/bcsj.55.865

The reaction of (8-oxo-5,6,7,8-tetrahydro-1-naphthyloxy)acetic acids with acetic anhydride and sodium acetate give a mixture of 4,5-dihydro-3H-naphtho<1,8-bc>furans and lactones.The relative yiels of 4,5-dihydro-3H-naphtho<1,8-bc>furans and lactones varied according to kinds of substituents on the benzene ring of (8-oxo-5,6,7,8-tetrahydro-1-naphthyloxy)acetic acids.Substituents which make the methylene group approach closer to the carbonyl carbon atom of (8-oxo-5,6,7,8-tetrahydro-1-naphthyloxy)acetic acids by a steric effect seem to favor the production of 4,5-dihydro-3H-naphtho<1,8-bc>furans.On the other hand, substituents which make the methylene group separate from the carbonyl carbon atom seem to favor the production of lactones.An electron-withdrawing chlorine atom on the benzene ring of (8-oxo-5,6,7,8-tetrahydro-1-naphthyloxy)acetic acids also favors the production of 4,5-dihydro-3H-naphtho<1,8-bc>furans.