Convergent synthesis of a tetrasaccharide repeating unit of the O-specific polysaccharide from the cell wall lipopolysaccharide of Azospirillum brasilense strain Sp7

• Pintu Kumar Mandal,
• Debashis Dhara and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2014, 10, 293–299, doi:10.3762/bjoc.10.26

• use of Et2O in the reaction solvent facilitated the formation of 1,2-cis glycoside as the major product. The concept of the Fraser–Reid’s “armed–disarmed” effect was successfully exploited in this glycosylation reaction [34][35]. Compound 5 acted as an activated or armed glycosyl donor because of the

• “armed–disarmed” effect as well as the removal of PMB ether in a one-pot reaction following the glycosylation reduced the overall number of steps. Experimental General methods All reactions were monitored by thin-layer chromatography over silica gel-coated TLC plates. TLC spots were visualized by warming

Gold-catalyzed glycosidation for the synthesis of trisaccharides by applying the armed–disarmed strategy

• Abhijeet K. Kayastha and
• Srinivas Hotha

Beilstein J. Org. Chem. 2013, 9, 2147–2155, doi:10.3762/bjoc.9.252

• conditions. Keywords: alkynes; armed–disarmed effect; glycosidation; gold; Introduction Observations that gold(III) has a great affinity for alkynes placed the chemistry of gold in an enviable situation that culminated into the total synthesis of several natural products, in which gold-mediated reactions

• -catalyzed glycosidation reactions (Scheme 7). Conclusion In conclusion, the armed–disarmed effect in propargyl glycosides in the presence of a catalytic amount of gold salts is studied. The high temperature of the glycosidation was found to be partially responsible for the cleavage of the interglycosidic

• hydrolysis and synthesis of a glycerol mannoside. Armed–disarmed effect in Ech-glycosides during gold-catalyzed reactions. Gold-catalyzed glycosidation at ambient temperature for the synthesis of trimannoside 25. Gold-catalyzed glycosidation at ambient temperature for the synthesis of higher saccharides