A Facile Synthesis of Novel Acyclo-C-Nucleoside Analogues from l-Rhamnose via Variants of Bohlmann-Rahtz Reaction
作者:Srinivas Kantevari、Siddamal Putapatri
DOI:10.1055/s-0030-1258038
日期:2010.9
Synthesis of a series of novel acyclo-C-nucleoside analogues bearing substituted pyridines, dihydro-6H-quinolin-5-ones, dihydro-5H-cyclopentapyridin-5-one, tetrahydrocyclohepta[b] pyridine-5-one, and azafluorinone has been achieved in very good yields, through CeCl3Ë7H2O-NaI-catalyzed one-pot condensation of a variant of the Bohlmann-Rahtz reaction using β-enaminones derived from l-rhamnose, acyclic and cyclic 1,3-dicarbonyls, and ammonium acetate. Ready availability of reactive β-enaminones, use of a cerium catalyst, and shorter reaction times are the advantages of this protocol over previous methodology. A plausible mechanism invoking cerium-catalyzed sequential Michael addition-cyclodehydration-elimination reactions is also presented.
合成了一系列带有取代吡啶、二氢-6H-喹啉-5-酮、二氢-5H-环戊吡啶-5-酮、四氢环庚[b]吡啶-5-酮和氮杂氟酮的新型无环-C-核苷类似物通过 CeCl3→7H2O-NaI 催化的 Bohlmann-Rahtz 反应变体的一锅缩合,使用源自 l-鼠李糖、无环和环状 1,3-二羰基和乙酸铵的 β-烯胺酮,获得了非常好的收率。反应性β-烯胺酮的现成可用、铈催化剂的使用和更短的反应时间是该协议相对于以前的方法的优点。还提出了一种可能的机制,涉及铈催化的连续迈克尔加成-环化脱水-消除反应。