17α-Hydroxy-3-methoxy-8, 14-secoestra-1, 3, 5 (10), 9-tetraen-14-one (IIa) which is an intermediate for the total synthesis of estrogens has been optically resolved. The isomer which has unnatural configuration at C-13 has been converted to estrapentaene 3-methyl ether (IVa) via the 9, 14-epoxy intermediates (XI, XII, XIII, XV).
![2-[2-(6-methoxy-3,4-dihydro-2H-naphthalen-1-ylidene)ethyl]-2-methylcyclopentane-1,3-dione Structure](https://image.chemsrc.com/caspic/000/899-79-6.png)
