马来酸酐   、                                                                                      
[(2R,3S,4R)-3,4-diacetyloxy-5-ethenyl-3,4-dihydro-2H-pyran-2-yl]methyl acetate                                                                                                                                                                                              以
                                                                                         
苯                                                                                  为溶剂,
                                                                                                                                                    反应 18.0h,
                                                                                                                生成                                                 [(2R,3S,4R,6aS,9aS,9bS)-3,4-diacetyloxy-7,9-dioxo-3,4,6,6a,9a,9b-hexahydro-2H-furo[3,4-h]chromen-2-yl]methyl acetate   、                                                                                             [(2R,3S,4R,6aR,9aR,9bR)-3,4-diacetyloxy-7,9-dioxo-3,4,6,6a,9a,9b-hexahydro-2H-furo[3,4-h]chromen-2-yl]methyl acetate