2-Methoxy-3-[2-(2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo[6.1.1.02,6]dec-4-yl)-2-(trimethylsilanyl-amino)-ethyl]-benzoic acid tert-butyl ester 、
[4-(tert-butoxycarbonylamino-methyl)-1-nitromethyl-cyclohexyl]-acetic acid 在
crude product 、 silica gel 、
ethyl acetate n-hexane 作用下,
生成 3-[2-{2-[4-(tert-Butoxycarbonylamino-methyl)-1-nitromethyl-cyclohexyl]-acetylamino}-2-(2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo[6.1.1.02,6]dec-4-yl)-ethyl]-2-methoxy-benzoic acid tert-butyl ester