Author's Organization：Institute of Applied Microbiology, University of Tokyo Institute of Applied Microbiology, University of Tokyo Shinagawa Plant, Sankyo Co., Ltd.
Reduction of the ⊿8-double bond in 3, 11β-dihydroxyestra-1, 3, 5 (10), 8-tetraen-17-one (II) was carried out. Catalytic hydrogenation of II occurred from rear side and afforded the compound having 8α, 9α-configuration, which was assigned in consideration of its resistance to acetylation and by leading to 9 (11)-dehydro-8-isoestrone methyl ether, whereas reduction of II with lithium in liquid ammonia afforded estradiol.
