4-spiro(33-dibromo)cyclopropane-5α-cholestan-3β-ol tetrahydropyranyl ether                                                                                                                                                              在
                                                                                                                                                                                 
甲基锂                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
乙醚                                                                                  为溶剂,
                                                                                                                                                                                        以100%的产率得到2-[(3S,5R,8S,9S,10R,13R,14S,17R)-17-((R)-1,5-Dimethyl-hexyl)-10,13-dimethyl-4-vinylidene-hexadecahydro-cyclopenta[a]phenanthren-3-yloxy]-tetrahydro-pyran