描述:
                                
                                                                                                                         3-carboxy-3-(5-methoxy-1,2-dihydrobenzocyclobuten-1-yl)-6,9-divinyl-1-oxaspiro[4,4]nonan-2-one (1,2:5,6-di-O-isopropylidene-α-D-glucofuranos-3-yl) ester                                                                                                                                                                                                                                                                                                          以41.3%的产率得到(8α,9β,14β)-11α-carboxy-11β,13β-(γ-lactone)-2-methoxy-17β-vinylgona-1,3,5(10)-triene (1,2:5,6-di-O-isopropylidene-α-D-glucofuranos-3-yl) ester