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.
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
pathway for the synthesis of tetracyclic purinium salts via ruthenium-catalyzed electro-oxidative annulation of C6-arylpurine nucleosides with alkynes without a stoichiometric metal oxidant has been developed. The protocol described herein exhibits high regioselectivity, broad scope, and wide functional group tolerance, allowing efficient coupling of various biologically important molecules including
Ring-Centered Heterocyclic Cations and the Direct Heteroarylation of Aromatic and Heterocyclic Compounds<sup>1</sup>
作者:Fenhong Song、Valentine R. St. Hilaire、Emil H. White
DOI:10.1021/ol990310q
日期:1999.12.1
[GRAPHICS]The protonation of heterocyclic diazotates (attachment adjacent to a nitrogen atom) yields ring-centered heterocyclic carbocations that are highly reactive. The carbocations were found to alkylate aromatic and heterocyclic compounds, such as benzene, N-methylpyrrole, and 2-aminopyridine, in reactions that are synthetically useful. This carbocation involvement may serve as a paradigm for the cross-linking of DNA by nitrous acid and the anticancer activity of heterocyclic diazotates.
Facilitating Rh-Catalyzed C–H Alkylation of (Hetero)arenes and 6-Arylpurine Nucleosides (Nucleotides) with Electrochemistry
An electrochemical approach to promote the ortho-C–H alkylation of (hetero)arenes via rhodium catalysis undermildconditions is described. This approach features mildconditions with high levels of regio- and monoselectivity that tolerate a variety of aromatic and heteroaromatic groups and offers a widely applicable method for late-stage diversification of complex molecular architectures including