作者:Yoshinori Yamamoto、Setsuko Onuki、Masatoshi Yumoto、Naoki Asao
DOI:10.3987/com-97-s(n)71
日期:——
The reaction of allyltributyltin with methyl 2-[N-((4S)-4-(1-methylethyl)-2-oxazolidinone-3-carbamoyl)amino]-2-bromoacetate (5a) was accelerated at -50 degrees C in the presence of AIBN and stopped in the presence of galvinoxyl, indicating that the reaction proceeds through a radical mechanism. The reaction was accelerated dramatically at -78 degrees C in the presence of ZnCl2 . OEt2, and the ZnCl2-mediated reaction was stopped in the presence of galvinoxyl. In the presence of 2 equiv ZnCl2 . OEt2, the reaction afforded methyl (2R)-2-[N-((4S)-4-(1-methylethyl)-2-oxazolidinone-3- carbamoyl)amino]4-pentenoate 6a(R)} with high diastereoselectivity (93:7). Taken together, ZnCl2 . OEt2 works as a radical initiator as well as chelating agent.