Stereoselective Synthesis of 1‘-<i>C</i>-Branched Arabinofuranosyl Nucleosides via Anomeric Radicals Generated by 1,2-Acyloxy Migration
作者:Kazuhiro Haraguchi、Yoshiharu Itoh、Kouichiro Matsumoto、Kyoko Hashimoto、Kazuo T. Nakamura、Hiromichi Tanaka
DOI:10.1021/jo020620d
日期:2003.3.1
formation at the anomeric position of uracil and adenine nucleoside has been accomplished through reaction of the anomeric radical, generated by 1,2-acyloxy migration, with a radical acceptor. The present method consists of the following steps: (1) electrophilic addition (bromo-pivaloyloxylation) to 3',5'-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)-protected 1',2'-unsaturated nucleoside, (2) tin radical-mediated
尿嘧啶和腺嘌呤核苷异头位置的立体选择性CC键形成是通过由1,2-酰氧基迁移产生的异头自由基与自由基受体的反应完成的。本方法由以下步骤组成:(1)亲电加成(溴-新戊酰氧基化)到3',5'-O-(1,1,3,3-四异丙基二硅氧烷-1,3-二基)保护的1', 2'-不饱和核苷,(2)锡自由基介导的加合物与自由基受体的反应。烯丙基(三丁基)锡的使用以66%的产率产生了1′-C-烯丙基化的尿嘧啶核苷14以及未重排的2′-C-烯丙基化的产物15(6%)。在5的反应中也可以使用苯乙烯基(三丁基)锡和3-溴-2-甲基丙烯腈之类的自由基受体。得到16(70%)和17(76%),而不会形成未重排的产品。还研究了腺嘌呤对应物12的自由基介导的CC键形成。