The synthesis, characterization, and alkylation of nacnac chromium triflate derivatives

A Cr(III) triflate coordinated by the bulky β-diketiminate ^MeL^iPr (^MeL^iPr = 2,4-pentane N,N′-bis(2,6-diisopropylphenyl)diketiminate) was synthesized from the corresponding bridging iodide complex [^MeL^iPrCr(μ-I)]₂ by ligand substitution and subsequent oxidation with silver triflate (AgOTf). ^MeL^iPr Cr^III(OTf)₂ exhibits rare trigonal bipyramidal geometry about Cr(III). Attempts to alkylate this triflate synthon with 1,4-dilithiobutane (Li(CH₂)₄Li) led to reduction, while reaction with dimethylzinc (ZnMe₂) led to a mono-alkylated product; only the reaction with methyl lithium (MeLi) was successful in generating a dialkyl.     

Glycosylation of allyl 2-acetamido-4,6-O-benzylidene-2-deoxy-alpha-D-glucopyranoside with bulky substituted glycosyl donors

Glycosylation of allyl 2-acetamido-4,6-O-benzylidene-2-deoxy-alpha-D-glucopyranoside with bulky substituted glycosyl donors leads to the formation of derivatives of the disaccharide alpha-D-Glc-(1-->3)-d-GlcNAc with different yields.     

Synthesis of carbasugar-containing non-glycosidically linked pseudodisaccharides and higher pseudooligosaccharides

This minireview covers synthetic methods towards carbasugar-containing non-glycosidically linked pseudodisaccharides or higher pseudooligosaccharides. Carbocyclic pyranose mimetics (saturated or unsaturated between C-5 and C-5a) are linked by ether, thioether or amine bridges to carbohydrates or other carbasugars.