2,3-丁二烯酸乙酯   、                                                                                      
7-(1-[(1,1-dimethylethyl)dimethylsilyloxy]ethenyl)-6,6,8-trimethyl-1,4-dioxaspiro-[4.5]dec-7-ene                                                                                                                                                              在
                                                                                                                                                                                 
对苯二酚                                                                                                                                  作用下,
                                                                                                                                                                                        反应 336.0h,
                                                                                                                以26.5%的产率得到ethyl (4'aRS,5'SR)-1',1',4'a-trimethyl-6'-methylene-3',4',4'a,5',6',7'-hexahydro-8'-[(1,1-dimethylethyl)dimethylsilyloxy]-1'H-spiro[[1,3]-dioxolane-2-2'-naphthalene]-5'-carboxylate