2-(4-acetoxyphenyl)-4-methyl valeric acid 、
methyl 2(S)-amino-4-(2(R)-(3,3-dimethylbutanoylamino)-2(R)-(methoxycarbonyl)ethylthio) butyrate 在
(benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate 、
N,N-二异丙基乙胺 作用下,
以
二氯甲烷 、
水 为溶剂,
以94%的产率得到methyl 2(S)-(2(R,S)-(4-acetyloxyphenyl)-4-methylpentanoylamino)-4-(2(R)-(3,3-dimethylbutanoylamino)-2(R)-(methoxycarbonyl)ethylthio) butyrate