ethyl (E)-4-[[(1E)-buta-1,3-dienoxy]-ditert-butylsilyl]oxybut-2-enoate                                                                                                                                                                                              以
                                                                                         xylene                                                                                  为溶剂,
                                                                                                                                                                                        生成                                                 ethyl (4aR,5R,8aR)-2,2-ditert-butyl-4a,5,6,8a-tetrahydro-4H-1,3,2-benzodioxasiline-5-carboxylate   、                                                                                             
ethyl (4aS,5S,8aR)-2,2-ditert-butyl-4a,5,6,8a-tetrahydro-4H-1,3,2-benzodioxasiline-5-carboxylate