9-amino-7-methylhomocamptothecin   、                                                                                      
对甲基苯甲醛                                                                                                                                                              在
                                                                                                                                                                                 
吡啶   、                                                                                                  
ytterbium(III) triflate                                                                                                                                  作用下,
                                                                                                                                                                                                                            以33%的产率得到20-ethyl-20-hydroxy-10-methyl-8-[(4-methylphenyl)methylideneamino]-17-oxa-3,13-diazapentacyclo[11.9.0.02,11.04,9.015,21]docosa-1(22),2,4(9),5,7,10,15(21)-heptaene-14,18-dione