methyl betulonate 、
乙炔基溴化镁 以
四氢呋喃 为溶剂,
反应 4.0h,
以68%的产率得到methyl (1R,3aS,5aR,5bR,7aR,9R,11aR,11bR,13aR,13bR)-9-ethynyl-9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-prop-1-en-2-yl-2,3,4,5,6,7,7a,10,11,11b,12,13,13a,13b-tetradecahydro-1H-cyclopenta[a]chrysene-3a-carboxylate