(E)-5-(6-Hydroxymethyl-3-methyl-4-oxo-1-oxa-spiro[4.4]nona-2,6-dien-2-yl)-4,4-dimethyl-pent-2-enoic acid ethyl ester                                                                                                                                                              在
                                                                                                                                                                                 
potassium carbonate                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
甲醇   、                                                                                         
水                                                                                  为溶剂,
                                                                                                                                                    反应 12.0h,
                                                                                                                以91.5%的产率得到(E)-5-(6-Hydroxymethyl-3-methyl-4-oxo-1-oxa-spiro[4.4]nona-2,6-dien-2-yl)-4,4-dimethyl-pent-2-enoic acid