Switching between <i>X</i>-Pyrano-, <i>X</i>-Furano-, and Anhydro-<i>X</i>-pyranoside Synthesis (X = C, N) under Lewis acid Catalyzed Conditions
作者:Youngran Seo、Jared M. Lowe、Neyen Romano、Michel R. Gagné
DOI:10.1021/acs.orglett.1c01713
日期:2021.8.6
A variety of C-glycosides can be obtained from the fluoroarylborane (B(C6F5)3) or silylium (R3Si+) catalyzed functionalization of 1-MeO- and per-TMS-sugars with TMS-X reagents. A one-step functionalization with a change as simple as the addition order and/or Lewis acid and TMS-X enables one to afford chiral synthons that are common (C-pyranosides), have few viable synthetic methods (C-furanosides)
各种C-糖苷可以从氟芳基硼烷(B(C 6 F 5 ) 3 )或硅基(R 3 Si + )催化的1-MeO-和全TMS-糖与TMS-X试剂的官能化获得。一步功能化只需简单地改变加成顺序和/或路易斯酸和 TMS-X,即可获得常见的手性合成子( C-吡喃糖苷),但几乎没有可行的合成方法( C-呋喃糖苷),或实际上是未知的(脱水-C-吡喃糖苷),其机械地分别由是否发生直接取代、异构化/取代或取代/异构化而产生。
Microwave-assisted efficient synthesis of aryl ketone β-C-glycosides from unprotected aldoses
Condensation between unprotected aldoses and dibenzoylmethane catalyzed by NaHCO(3) in the cosolvents EtOH and H(2)O (4:1) under microwave irradiation gave aryl ketone beta-C-glycosides 6b-i in higher yields (from 50% with C-riboside 6g up to 99% with C-glucoside 6b) and better anomeric selectivities (beta-configuration >95%) in a shorter reaction time (90 min), compared with previous conventional
Knoevenagel Condensation between C-glycoside and Active Methylene Compounds without Catalysts
作者:Xiaomin Gu、Zhijie Fang
DOI:10.3184/174751916x14762012580355
日期:2016.11
based aromatic aldehyde and cyclic activemethylenecompounds such as barbituric acid, thiobarbituric acid, 1,3-dimethylbarbituric acid, 5,5-dimethyl-1,3-cyclohexanedione, 2,2-dimethyl-1,3-dioxane-4,6-dione and 3-methyl-1-phenyl-2-pyrazolin-5-one has been developed, to give a series of unusual fused heterocyclic compounds. The structures of all the new compounds were established by the spectral data
Synthesis of a small library of oximes and phenylhydrazones of phenyl ketone <i>C</i>-glycosides
作者:Xiaomin Gu、Zhijie Fang
DOI:10.1080/07328303.2016.1227830
日期:2016.6.12
ABSTRACT An efficient and convenient route was developed for the synthesis of oximes, the corresponding O-methylated oximes, and phenylhydrazones from phenyl ketone C-glycosides in medium to high yields. The broad substrate and reagent scope of this method expands the potential of applying phenyl ketone C-glycosides to the synthesis of important bioactive molecules.
C-Glycosides by Aqueous Condensation of β-Dicarbonyl Compounds with Unprotected Sugars
作者:I. Riemann、W.-D. Fessner、M. A. Papadopoulos、M. Knorst
DOI:10.1071/ch02012
日期:——
water, under mildly alkaline conditions, provides a�convenient and effective route to C-glycosidic ketones in high yields. Reactions usually proceed with high β`anomeric' stereoselectivity because product composition is determined by thermodynamic control. Mechanistically, the condensation follows a typical Knoevenagel scheme, after which an intramolecular oxa-Michael cyclization determines C-glycoside