methyl 15,16-dihydro-15,16-dihydroxyisopimarate 、
丙酮 在
copper(II) sulfate 作用下,
反应 16.0h,
以75%的产率得到(1R,4aR,4bS,7S,10aR)-7-(2,2-Dimethyl-[1,3]dioxolan-4-yl)-1,4a,7-trimethyl-1,2,3,4,4a,4b,5,6,7,8,10,10a-dodecahydro-phenanthrene-1-carboxylic acid methyl ester