Transition-Metal-Free Synthesis of C‑Glycosylated Phenanthridines via K2S2O8‑Mediated Oxidative Radical Decarboxylation of Uronic Acids

• Published in: Journal of organic chemistry Vol. 83; no. 2; pp. 588 - 603
• Main Authors: Zhou, Xin, Wang, Peng, Zhang, Li, Chen, Pengwei, Ma, Mingxu, Song, Ni, Ren, Sumei, Li, Ming
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 19.01.2018; Amer Chemical Soc
• Subjects: beta-cyclodextrin; Chemistry; Chemistry, Organic; decarboxylation; free radicals; homolytic cleavage; moieties; organic chemistry; phenanthridines; Physical Sciences; protocols; Science & Technology; transition elements; uronic acids; H FUNCTIONALIZATION; LEAD-TETRAACETATE; NUCLEOSIDE ANALOGS; COUPLING REACTIONS; SELECTIVE CLEAVAGE; CARBOHYDRATE RADICALS; PROTECTING GROUPS; CYCLODEXTRINS; DERIVATIVES; EFFICIENT METHOD
• ISSN: 0022-3263; 1520-6904; 1520-6904
• DOI: 10.1021/acs.joc.7b02346

We have developed an efficient protocol for the synthesis of C-glycosylated phenanthridines. Tetrafuranos-4-yl and pentapyranos-5-yl radicals, generated from K2S2O8-mediated oxidative decarboxylation of furan- and pyranuronic acids, undergo attack to 2-isocyanodiphenyls and ensuing homolytic aromatic substitution to provide diverse C-glycosylated phenanthridines in satisfactory yields without resort to transition metals. This reaction tolerates various functional groups, and enables ready synthesis of complex oligosaccharide-based phenanthridines. The C-glycosylated phenanthridine derived from β-cyclodextrin has been prepared, which might be potential in medicinal and biological chemistry due to its flexible conformation.