New Applications of 1,5-Hydrogen Atom Transfer Reactions: Self-Oxidizing Protecting Groups
作者:Dennis P. Curran、Hosung Yu
DOI:10.1055/s-1992-34173
日期:——
Three new alcohol protecting groups are introduced: o-bromobenzyl, o-bromo(methylenedioxy)benzyl, and o-bromotrityl. Removal of these protecting groups under reductive conditions with tributyltin hydride is coupled with an oxidation of the substrate to produce directly an aldehyde or ketone. This oxidation occurs by 1,5-hydrogen transfer, followed by ß-fragmentation. For example, treatment of the o-bromobenzyl ether of 3-phenyl-1-propanol with tibutyltin hydride at 0.001 M (80°C) directly produces 3-phenyl-1-propanal. An application to the selective oxidation of primary alcohols in the presence of secondary alcohols is also introduced.
新介绍了三种保护醇的基团:邻溴苄基、邻溴(亚甲二氧基)苄基和邻溴三苯甲基。在还原条件下,用三丁基锡氢化物去除这些保护基团,同时将底物氧化,直接生成醛或酮。这种氧化过程是通过1,5-氢转移,随后发生β-碎片化完成的。例如,在0.001 M浓度下(80°C)用三丁基锡氢化物处理3-苯基-1-丙醇的邻溴苄基醚,直接生成3-苯基-1-丙醛。还介绍了在存在二级醇的情况下选择性氧化一级醇的应用。