Silver-Catalyzed Direct C6-H Arylation of Purines and Purine Nucleosides with Arylboronic Acids
作者:Miao Tian、Mingwu Yu、Tingting Shi、Junbin Hu、Shunlai Li、Jiaxi Xu、Ning Chen、Hongguang Du
DOI:10.1002/ejoc.201700406
日期:2017.6.30
An efficient protocol for the direct C6–H arylation of purines and purine nucleosides is described under the catalysis of silver nitrate and under ambient conditions. A wide assortment of purines and arylboronic acids can be employed in this process to afford C6‐arylpurines and purine nucleosides with high regioselectivity. TFA = trifluoroacetic acid; DCE = 1,2‐dichloroethane.
An efficient method for the synthesis of 6-arylpurines (nucleosides) was developed via Suzuki–Miyaura cross-coupling reactions of 6-chloropurines (nucleosides) and sodium tetraarylborate in neat water (ethanol). The process gave good to high isolated yields within a short reaction time under microwave irradiated conditions.
RhIII-catalyzed C–H activation/annulation of 6-arylpurine nucleosides with alkynes under mild reaction conditions. The resulting products displayed tunable photoluminescence covering most of the visible spectrum. Mechanistic insights delineated the rhodium catalyst’s mode of action. A purinoisoquinolinium-coordinated rhodium(I) sandwich complex was well characterized and identified as the key intermediate
Pd(II)-Catalyzed <i>Ortho</i> Arylation of 6-Arylpurines with Aryl Iodides via Purine-Directed C−H Activation: A New Strategy for Modification of 6-Arylpurine Derivatives
Purine is utilized as a new directing group for the Pd-catalyzed monoarylation of 6-arylpurines with simple aryl iodides via C H bond activation in good yields, providing a complementary tool for the modification of 6-arylpurines (nucleosides). Most importantly, purine can be used as a building block for nucleoside derivatives, and the use of purine as a directing group helps avoid additional synthetic steps.