Characterization of the Isochromen-4-yl-gold(I) Intermediate in the Gold(I)-Catalyzed Glycosidation of Glycosyl ortho-Alkynylbenzoates and Enhancement of the Catalytic Efficiency Thereof
作者:Yugen Zhu、Biao Yu
DOI:10.1002/anie.201103409
日期:2011.8.29
Gold standard: The title gold complex (see scheme) was characterized unambiguously as an important intermediate in the title reaction. Protonolysis of this vinyl gold(I) complex was critical for regeneration of the active gold(I) species for the catalytic cycle, and use of a protic acid co‐catalyst significantly lowered the required catalyst loading to 0.5 mol %.
Significant Substituent Effect on the Anomerization of Pyranosides: Mechanism of Anomerization and Synthesis of a 1,2-<i>cis</i>Glucosamine Oligomer from the 1,2-<i>trans</i>Anomer
作者:Shino Manabe、Hiroko Satoh、Jürg Hutter、Hans Peter Lüthi、Teodoro Laino、Yukishige Ito
DOI:10.1002/chem.201303474
日期:2014.1.3
Aminoglycosides containing a 2,3‐trans carbamate group easily undergo anomerization from the 1,2‐trans glycoside to the 1,2‐cis isomer under mild acidic conditions. The N‐substituent of the carbamate has a significant effect on the anomerization reaction; in particular, an N‐acetyl group facilitated rapid and complete α‐anomerization. The differences in reactivity due to the various N‐substituents were
Total Synthesis and Structural Revision of TMG-chitotriomycin, a Specific Inhibitor of Insect and Fungal β-<i>N</i>-Acetylglucosaminidases
作者:You Yang、Yao Li、Biao Yu
DOI:10.1021/ja9055245
日期:2009.9.2
beta-N-acetylglucosaminidases that possesses an unique N,N,N-trimethyl-d-glucosamine (TMG) residue, is revised to be the TMG-beta-(1-->4)-chitotriose instead of the originally proposed alpha-anomer via its total synthesis, for which a highly convergent approach was developed in which the sterically demanding (1-->4)-glycosidic linkages are efficiently constructed by the Au(I)-catalyzed glycosylation protocol with glycosyl