Regioselective Isomerisation of Highly Substituted 1-Methylenecyclohexenepoxides to the Corresponding Allylic Alcohols. Influence of the Base and of the Protecting Groups
作者:Stefan Kirsch、Olaf Ackermann、Klaus Harms、Thorsten Bach
DOI:10.1007/s00706-003-0153-7
日期:2004.6.1
Highly substituted 1-methylenecyclohexenepoxides 3 , useful building blocks for a projected synthesis of wailupemycin A ( 1 ), were synthesized from ( R )-carvone in eight synthetic steps in 23–40% overall yield. The regioselectivity of the subsequent isomerisation to the corresponding allylic alcohols was shown to depend on the basicity of the reagent and on the bulkiness of the protecting groups
由( R )-香芹酮经八个合成步骤合成了高度取代的1-亚甲基 环己烯氧化物 3 ,这是预期合成Wailupemycin A( 1 )的 有用组成部分, 总产率为23-40%。随后的异构化反应对相应的烯丙基醇的区域选择性显示取决于试剂的碱性和 3中 存在的保护基的体积 。用二乙基 铝2,2,6,6-四甲基哌啶( DATMP ),仅形成仲烯丙基醇 5 。用强碱如二锂的混合物 异 -propylamide和钾 叔 -丁醇 盐( LIDAKOR ),主要是叔烯丙醇 6 。