ethyl (1R,6R,7S,9S)-7-methoxy-4-methyl-9-tosyl-3,8-dioxabicyclo[4.2.1]non-4-ene-5-carboxylate                                                                                                                                                              在
                                                                                                                                                                                 
三氟乙酸                                                                                                                                  作用下,
                                                                                                                                                                                        反应 2.0h,
                                                                                                                以80%的产率得到ethyl (2R,3S,3aR,6aS)-2-(hydroxymethyl)-5-methyl-3-(4-methylphenyl)sulfonyl-2,3,3a,6a-tetrahydrofuro[2,3-b]furan-4-carboxylate