5,6-dihydrospiro[benzo[1,2-b:5,4-b']difuran-3,3'-indol]-2'(1'H)-one   、                                                                                      3-methylspiro[furo[3,2-f][1,2]benzisoxazole-5,3'-indol]-2'(1H)-one   、                                                                                      
(S)-(+)-5-羟甲基-2-吡咯烷酮对甲苯磺酸酯   、                                                                                      
2-溴甲基-5-三氟甲基呋喃                                                                                                                                                                                                                                                                                                          以1′-{[(2S)-5-oxopyrrolidin-2-yl]methyl}-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one was obtained (47%) as a colorless solid的产率得到1'-{[(2S)-5-oxopyrrolidin-2-yl]methyl}-5,6-dihydrospiro[benzo[1,2-b:5,4-b']difuran-3,3'-indol]-2'(1'H)-one