Stereoselective Synthesis of 2,3‐Diamino‐2,3‐dideoxyglycosides from 3‐O‐Acetyl‐2‐nitroglycals

Abstract

2‐Nitroglycal is a widely used synthon for aminoglycosides synthesis. Herein, we report an efficient method for 2‐nitroglycals synthesis using nBu4NNO3/Tf2O/DTBMP. Using 3‐O‐acetyl‐2‐nitroglycals as donors, a novel method for the construction of challenging 1,2‐cis‐2,3‐diamino‐2,3‐dideoxyglycosidic linkages was established using 4‐pyrrolidinopyridine (PPY) mediated relay glycosylation reaction. The method enjoys many features, including very mild reaction condition, excellent regio‐ and stereoselectivity, good to excellent yields and broad substrate scope.

Stereoselective Synthesis and Immunological Evaluation of Common O‐antigen of P. mirabilisOE and P. vulgarisTG103

“…[ 30‐39 ] In a continuing investigation on organo‐catalysis stereoselective glycosylation, we have developed the conformation‐ restrained 2‐nitroglycal donors for stereoselective generation of 1,2‐ cis ‐2‐amino/acetamido‐2‐deoxy‐glycosidic linkages via bifunctional organo‐thiourea catalysis glycosylation. [ 40‐43 ] In this work, the conformation‐restrained 2‐nitroglycal donors could be used for 1,2‐ cis ‐2‐acetamido‐2‐deoxy‐glycosidic bonds formation. Second, there have been documented the special issue for long oligosaccharide synthesis: glycosylation efficiency, functional groups transformation and protecting groups manipulation.…”

“…Next, acetylation furnished fully protected trisaccharide glycal 19 in 97% yield, which was successfully transformed to trisaccharide building block 2‐nitrogalactal 9’ by use of our newly developed method in 68% yield. [ 41 ]…”

Stereoselective Synthesis of the O‐antigen of A. baumannii ATCC 17961 Using Long‐Range Levulinoyl Group Participation

“…Synthesis of 2,3-diamino-2,3-dideoxysugar was a challenge work, and we just developed an efficient method by use of 3-O-acetyl-2-nitroglycal to obtain this rare sugar. [22] Therefore, using our newly developed method, the desired 2-nitro-3-azide-glucoside 16 was obtained in 68 % yield from 3-O-acetyl-2-nitroglucal 15 which was synthesized from glucal in 6 steps (details in Supporting Information). [22] Reduction of the nitro and azide group, acylation by trichloroacetyl chloride (TCACl), and removal of the silyl group by tetrabutylammonium fluoride (TBAF) gave compound 17 in 53 % yield over three steps.…”

“…[22] Therefore, using our newly developed method, the desired 2-nitro-3-azide-glucoside 16 was obtained in 68 % yield from 3-O-acetyl-2-nitroglucal 15 which was synthesized from glucal in 6 steps (details in Supporting Information). [22] Reduction of the nitro and azide group, acylation by trichloroacetyl chloride (TCACl), and removal of the silyl group by tetrabutylammonium fluoride (TBAF) gave compound 17 in 53 % yield over three steps. [23] Oxidation of C6-OH using TEMPO/BAIB, followed by a benzylation afforded the key 2,3-di-trichloroacetamido-glucuronate intermediate 18.…”

Synthesis of 2‐Amino‐2‐deoxy‐1,3‐dithioidoglycosides via Organocatalytic Relay Glycosylation of 3‐O‐Acetyl‐2‐nitrogalactals

“…[ 38‐40 ] In addition, 2‐nitroglycals are powerful donors for the synthesis of bioactive 2‐amino‐2‐deoxy‐glycosides. [ 40‐48 ] And owing to our continuous interest in organocatalyzed stereoselective glycosylation and the successful synthesis of 2‐amino‐2‐deoxy‐ 1,3‐dithioglucosides/mannsides from 3‐ O ‐acetyl‐2‐nitroglucals via organocatalytic relay glycosylation, [ 25,49‐53 ] herein, we extended our newly developed method to synthesize more challenging bioactive 2‐amino‐2‐deoxy‐1,3‐dithioidoglycosides by the use of 3‐ O ‐acetyl‐2‐ nitrogalactals (Figure 1C). Attack of 4‐pyrrolidinopyridine (PPY) to galactal 1 , generates intermediate I , which may react with the glycosyl thiol acceptor 2 to yield 3,4‐ trans ‐product 3 .…”