3-Phenethyl-oxirane-2-carboxylic acid ethyl ester 、
(8S,9R,13R,14R)-3-amino-13-methyl-7,8,9,11,12,14,15,16-octahydro-6H-cyclopenta[a]phenanthren-17-one 在
yttrium(III) trifluoromethanesulfonate 作用下,
以
四氢呋喃 为溶剂,
以91 %的产率得到(±)-erythro-ethyl 2-hydroxy-3-(((8S,9R,13R,14R)-13-methyl-17-oxo-7,8,9,11,12,13,14,15,16,17-decahydro-6H-cyclopenta[a]phenanthren-3-yl)amino)-5-phenylpentanoate