Total synthesis of 3-hydroxy-6-oxaestra-1,3,5(10)-trien-17-one
Abstract
The modified steroid estrogen, 3-hydroxy-6-oxaestra-1,3,5(10)-trien-17-one, i.e. 6-oxaestrone 8 has been prepared from 7-methoxychromanone 1 by de novo synthesis of the modified steroid ring system. The 1H and 13C NMR data for the intermediate products 3, 4, 4a, 4b, 4c, 6, 7, and for the final product 8 support the proposed structures. A mechanism for the ring-closure reaction of 3 to intermediate products 4 and 4a is proposed.