A rapid and divergent access to chiral azacyclic nucleoside analogues via highly enantioselective 1,3-dipolar cycloaddition of β-nucleobase substituted acrylates

Abstract

A rapid and divergent access to chiral azacyclic nucleoside analogues has been established via highly exo-selective and enantioselective 1,3-dipolar cycloaddition of azomethine ylides with β-nucleobase substituted acrylates. Using 1 mol% of a chiral copper complex, various chiral azacyclic nucleoside analogues were obtained in high yields, excellent exo-selectivities and enantioselectivities (98 to >99% ee).

Asymmetric Ring Opening/Cyclization/Retro‐Mannich Reaction of Cyclopropyl Ketones with Aryl 1,2‐Diamines for the Synthesis of Benzimidazole Derivatives

“…The most common synthetic strategies are focused on the construction of benzimidazole backbones by using chiral precursors . With regard to the catalytic asymmetric transformation, several successful examples involving the direct enantioselective functionalization of prochiral benzimidazole compounds have been developed by the groups of Hartwig, Guo, and Terada . However, these strategies often require additional steps to prepare either the chiral precursors or prochiral benzimidazoles.…”

“…[1] Consequently,s ubstantial efforts have been dedicated to developing efficient methods toward their preparation. [3] With regard to the catalytic asymmetric transformation, several successful examples involving the direct enantioselective functionalization of prochiral benzimidazole compounds have been developed by the groups of Hartwig, [4] Guo, [5] and Te rada. [3] With regard to the catalytic asymmetric transformation, several successful examples involving the direct enantioselective functionalization of prochiral benzimidazole compounds have been developed by the groups of Hartwig, [4] Guo, [5] and Te rada.…”

Construction of benzimidazole-fused dihydrobenzoxazoles via Cu-catalyzed tandem C–H functionalization

“…所有药品试剂均为市售且未经纯化. 5-甲氧基-1H-苯并[d]咪唑(2c) [22] 、5-氟-1H-苯并[d]咪唑(2f) [22] 、5-溴 -1H-苯并[d]咪唑(2h) [22] 、乙基1H-苯并[d]咪唑-5-羧酸 乙酯(2e) [23] 、1H-萘并 [2,3-d]咪唑(2j) [24] 和[Cu(1,10-邻 菲啰啉)3]Br2 [25] 按照文献方法合成. 使用的石油醚的沸…”

Highly Enantioselective Synthesis of Chiral Cyclopropyl Nucleosides via Catalytic Asymmetric Intermolecular Cyclopropanation

“…However, the formation of 3-(purin-9-yl) allyl 2-diazoacetates always requires multiple steps. The catalytic asymmetric Michael-initiated ring-closure (MIRC) reactions of electrophilic alkenes with ylides or alkyl halides represent one of the most attractive routes to synthesize optically pure cyclopropanes. − In the context of ongoing projects for the synthesis of chiral nucleosides, we now wish to report an enantioselective construction of chiral cyclopropyl purine nucleoside analogues via asymmetric MIRC reactions of α-purine acrylates with α-bromo carbonyl compounds (Scheme c). It is noteworthy that the process yields the chiral cyclopropyl purine nucleoside analogues that have a chiral quaternary stereocenter, which would normally be challenging for construction with good stereocontrol by other methods …”