A Dinuclear Dysprosium Complex as an Air‐Stable and Recyclable Catalyst: Applications in the Deacetylation of Carbohydrate, Aliphatic, and Aromatic Molecules

Abstract

Twod inuclear Dy III complexes, [Dy 2 (hmb) 2 (OTf) 2 (H 2 O) 4 ]·HOTf·2THF (A·HOTf·2THF) and [Dy 2 (hmi) 3 (H 2 O) 2 ]·2HOTf (B·2HOTf), have been synthesized by the reaction of Dy(OTf) 3 and the Schiff-base ligands H 2 hmb (N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide) or H 2 hmi ((2-hydroxy-3-methoxyphenyl)methylene iso-nicotinohydrazine). Disarmed glycosyl trichloroacetimidates can be activated by complex A in the synthesis of 1,2-transglycosides with primary and secondary acceptors. This methodo ffers an efficient route to selectively deacetylated monosaccharides and disaccharides in high yields and a green catalystthat can be easily recycled and reused.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Total Synthesis of a Chimeric Glycolipid Bearing the Partially Acetylated Backbone of Sponge-Derived Agminoside E

“…Purification by silica gel flash chromatography (Hex/EtOAc 7:3 to 3:7) gave the desired compound 5a (457 mg, 75%) as a white amorphous solid: R f 0.5 (Hex/EtOAc 3:7). Physical and analytical data agreed with those published …”

“…Physical and analytical data agreed with those published. 60 4-Methylphenyl 3,4-Di-O-benzyl-β-D-thioglucopyranoside (19). To a cooled solution of compound 18 36 (2.27 g, 4.89 mmol, 1.0 equiv) in dry DCE (50 mL) at 0 °C was added BH 3 •THF (1.0 M in THF, 25 mL, 25 mmol, 5.0 equiv) followed by TMSOTf (135 μL, 0.744 mmol, 0.15 equiv).…”

Convergent Synthesis of the Octasaccharide Repeating Unit of the K55 Capsular Polysaccharide of Acinetobacter baumannii BAL_204 Strain

“…Hydrolysis of the anomeric thioethyl group in compound 16 by the treatment with NIS 30 in moistened CH 2 Cl 2 followed by treatment of the disaccharide hemiacetal derivative with trichloroacetonitrile in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) 31 furnished disaccharide trichloroacetimidate derivative 17 in 70% over all yield. HClO 4 -SiO 2 promoted stereoselective glycosylation of p-methylphenyl 2,3,6-tri-O-acetyl-1-thio--D-glucopyranoside (8) 22 with trichloroacetimidate derivative 17 furnished trisaccharide thioglycoside derivative 18 in 73% yield, which was confirmed by the NMR spectroscopic analysis [appearance of signals at  = 4.89 (br s, H-1 G ), 4.68 (br s, H-1 H ), 4.55 (d, J = 9.0 Hz, H-1 F ) in 1 H NMR and  = 99.4 (C-1 G ), 98.9 (C-1 H ), 85.5 (C-1 F ) in 13 C NMR spectra].…”

“…The synthesis of the desired octasaccharide has been achieved as its p-methoxyphenyl (PMP) glycoside (1) by stereoselective glycosylation of a number of monosaccharide intermediates 2, 16 3, 17 4, 18 5, 19 6, 20 7 21 and 8. 22 The key features of the synthetic strategy include (a) stereoselective convergent block [5+3] glycosylation; (b) application of a combination 23 of N-iodosuccinimide (NIS) and perchloric acid supported over silica (HClO 4 -SiO 2 ) 24 as thiophilic glycosylation activator for the thioglycoside donors; (c) activation of glycosyl trichloroacetimidate donors [25 by HClO 4 -SiO 2 ; (d) late-stage regioselective BAIB-TEMPO-mediated oxidation of 1° hydroxyl group to carboxylic acid in the presence of 2° hydroxyl groups; 26 (e) removal of benzyl ethers and benzylidene acetal under a catalytic transfer hydrogenation condition using triethylsilane as hydrogen source; 27 and (f) satisfactory stereochemical outcome around the glycosidic linkages in the glycosylation reaction. The pentasaccharide and trisaccharide components of the block [5+3] glycosylation were synthesized from the monosaccharide intermediates using sequential stereoselective glycosylations.…”

Heterocyclic-Additive-Activated Dinuclear Dysprosium Electrocatalysts for Heterogeneous Water Oxidation

“…Recently, the usage of rare-earth/lanthanide complexes as catalysts in both organic reactions , and polymerization processes , has attracted increasing attention. In previous work, lanthanide-based complexes containing Schiff-base ligands have been utilized for triggering CO 2 /epoxide copolymerization, in which all dinuclear dysprosium complexes are air-insensitive molecules and highly active in such a homogeneous catalytic system .…”