Transition-Metal-Free Synthesis of C-Glycosylated Phenanthridines via K<sub>2</sub>S<sub>2</sub>O<sub>8</sub>-Mediated Oxidative Radical Decarboxylation of Uronic Acids
作者:Xin Zhou、Peng Wang、Li Zhang、Pengwei Chen、Mingxu Ma、Ni Song、Sumei Ren、Ming Li
DOI:10.1021/acs.joc.7b02346
日期:2018.1.19
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.
我们已经开发出一种用于合成C-糖基化菲啶的有效方案。由K 2 S 2 O 8介导的呋喃酸和吡喃糖醛酸的氧化脱羧反应生成的四氢呋喃-4-基和五吡喃基-5-基遭受2-异氰基二苯基的攻击,随后发生均相芳族取代,从而提供多种C-糖基化的菲啶无需过渡金属即可获得令人满意的收率。该反应可耐受各种官能团,并能方便地合成复杂的基于寡糖的菲啶。已经制备了衍生自β-环糊精的C-糖基化菲啶,由于其灵活的构象,在医学和生物化学中可能具有潜力。
Silver‐Enabled General Radical Difluoromethylation Reaction with TMSCF
<sub>2</sub>
H
A silver‐mediated oxidative difluoromethylation of styrenes and vinyl trifluoroborates with TMSCF2H is reported for the first time. This method enables direct and facile access to CF2H‐alkenes from abundant alkenes with excellent functional‐group compatibility. Moreover, this Ag/TMSCF2H protocol could further enable a series of radical difluoromethylation reactions of a wide array of substrates, offering
Synthesis of 6-aroyl phenanthridines by Fe-catalyzed oxidative radical cyclization of 2-isocyanobiphenyls with benzylic alcohols
作者:Ziyi Nie、Qiuping Ding、Yiyuan Peng
DOI:10.1016/j.tet.2016.11.010
日期:2016.12
A practical method for the synthesis of 6-aroyl phenanthridine derivatives by Fe-catalyzed oxidative radicalcyclization of 2-isocyanobiphenyls with benzylic alcohols is described. In addition, this cyclization could be occurred by using toluene as aroyl source. The procedure tolerates various functional groups under simple conditions. A single-electron-transfer pathway is proposed according to mechanistic
6-Aroylated Phenanthridines via Base Promoted Homolytic Aromatic Substitution (BHAS)
作者:Dirk Leifert、Constantin Gabriel Daniliuc、Armido Studer
DOI:10.1021/ol403147v
日期:2013.12.20
2-isocyanobiphenyls react with aromatic aldehydes via base promoted homolytic aromatic substitution (BHAS) to give 6-aroylated phenanthridines. Reactions occur via addition of acylradicals to the isonitrile functionality and subsequent intramolecular BHAS of the intermediate imidoyl radicals. Initiation of the radicalchainreaction is best achieved with small amounts of FeCl3 (0.4 mol %), and the commercially
The benzoylperoxide (BPO)-promoted phenanthridinylation of simple alkanes with isonitrile is developed via C(sp(3))-H and C(sp(2))-H bond cleavage. This procedure is featured by dual C-C bond formation proceeding with the addition of an alkyl radical to isonitrile followed by radicalaromatic cyclization.