Various carbocyclic ribofuranosyl nucleosides were stereoselectively synthesized through a small number of steps from 2-azabicyclo[2.2.1]hept-5-en-3-ones by the use of sodium borohydride-mediated C-N bond cleavage as a key step. Ready availability of a novel synthetic precursor, (±)-4β-hydroxymethyl-1β-ureidocyclopentane-2α, 3α-diol [(±)-carbocyclic ribofuranosylurea], provides not only facile routes to carbocyclic robofuranosylpyrimidines, but also another route to the corresponding cyclopentylamine, (±)-1β-amino-4β-hydroxymethylcyclopentane-2α, 3α-diol [(±)-carbocyclic ribofuranosylamine], which is useful for the synthesis of the corresponding purine nucleosides.
通过利用
硼氢化钠介导的C-N键断裂作为关键步骤,从
2-氮杂双环[2.2.1]庚-5-烯-3-酮出发,经过少量步骤,立体选择性地合成了多种碳环
核糖呋喃糖苷核苷。新型合成前体(±)-4β-羟甲基-1β-
脲基
环戊烷-2α, 3α
-二醇[(±)-碳环
核糖呋喃糖苷
脲]的易得性,不仅提供了通往碳环
核糖呋喃糖苷
嘧啶的便捷途径,还提供了另一种途径,即合成相应的
环戊胺,(±)-1β-
氨基-4β-羟
甲基环戊烷-2α, 3α
-二醇[(±)-碳环
核糖呋喃糖苷胺],这对于相应
嘌呤核苷的合成非常有用。