作者:Michael E. Jung、Brian A. Duclos
DOI:10.1016/j.tet.2006.07.023
日期:2006.10
2-Methylcyclohexane-1,3-dione 14 was converted via the Wieland–Miescher analogue 15 into the 6-silyloxy-2,5,5,8a-tetramethyldecalin-1-one 21 by an efficient process. Several routes were examined to transform this compound into the pentacyclic triterpene skeleton of betulinic acid and its structural analogues. For example, the iodide 39, easily prepared from 21, was converted via a Sonogashira-hydroboration–Suzuki
通过高效的方法,通过Wieland-Miescher类似物15将2-甲基环己烷-1,3-二酮14转化为6-甲硅烷氧基-2,5,5,8a-四甲基十氢化萘-1-酮21。研究了几种途径将该化合物转化为桦木酸及其结构类似物的五环三萜骨架。例如,碘化物39很容易由21制备,通过Sonogashira-硼氢化-铃木工艺转化为E-三烯45。使用苯并蒽酮敏化剂对45进行光解后得到Z-三烯43。但是,所有试图使该三烯43环化成环己二烯47的尝试(通过光化学或热学方法是电环化的,金属催化的方法,氧化和自由基环化)均未能产生关键的五环材料。