The structure of the title compound, C29H26O4, prepared from 1-(6-methoxy-2
-naphthyl)propan-1-one and ethyl ortho-formate in the presence of boron tri
fluoride under microwave irradiation, consists of connected 7-methoxy-2-met
hyl-2,3-dihydro-1H-cyclopenta[a]naphthalen-3-one and 1-(6-methoxy-2-naphthy
l)propan-1-one units. The space group, Pc, is non-centrosymmetric but achir
al; three chiral centres exist in the molecule, but both enantiomers are pr
esent in the crystal.