(2-decyl-2-methyl-1,3-dioxolan-4-yl)methyl (4-nitrophenyl) carbonate   、                                                                                      [(1S,4R,5R,6R,11R,13S,17S,18S)-4,5,17-trihydroxy-6,14,18-trimethyl-9,16-dioxo-3,10-dioxapentacyclo[9.8.0.01,7.04,19.013,18]nonadec-14-en-8-yl] 3-hydroxy-4-methyl-3-propan-2-ylpentanoate                                                                                                                                                              在
                                                                                                                                         
4-二甲氨基吡啶                                                                                                                                                                          作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                                                        生成