Scalable Synthesis of Versatile Rare Deoxyamino Sugar Building Blocks from d-Glucosamine

Expanding the Scope of a One-Pot Double Displacement Protocol to Access the All-Rare-Sugar-Containing Trisaccharide Unit of Pseudomonas stutzeri OX1

Herein, we have explored a one-pot bis-triflation and regioselective displacement protocol with d-fucose 2,4-diol to access various rare 6-deoxy amino d-sugars. This strategy enabled the first total synthesis of the trisaccharide unit of Pseudomonas stutzeri OX1 strain containing d-perosamine and d-tomosamine. Installation of a 1,2-cis linkage and late-stage N-formylation are the key challenges in the total synthesis, which was accomplished via the longest linear sequence of 21 steps with 1.2% overall yield.

Chemical Synthesis of a Densely Functionalized Aminodisaccharide from Fusobacterium nucleatum ATCC 23726 O-Antigen

Fusobacterium nucleatum, a colorectal-cancer-associated oncomicrobe, can trigger or accelerate numerous pathologies. We report the first synthesis of a conjugation-ready disaccharide containing six amino groups from F. nucleatum ATCC 23726 O-antigen. Rare 2,3-diamido-d-glucuronic acid amide and 2-acetamido-4-amino-d-fucose were synthesized from d-glucosamine through configuration inversion, nucleophilic substitution, C6 oxidation, and C6 deoxygenation. A judicious choice of protecting groups and reaction conditions enabled the selective installation of N-acetyl, N-propanoyl, N-formyl, and carboxamido groups.

Sulfamate-Tethered Aza-Wacker Strategy for a Kasugamine Synthon

We present our preparation of a kasugamine synthon, which proceeds in 14 steps from a literature epoxide. We expect that this kasugamine derivative can be used for the total syntheses of kasugamycin, minosaminomycin, and analogue antibiotics. A key step in the synthesis is our laboratory's sulfamate-tethered aza-Wacker cyclization.

De Novo Synthetic Approach to 2,4-Diamino-2,4,6-trideoxyhexoses (DATDH): Bacterial and Rare Deoxy-Amino Sugars

A synthetic route to 2,4-diamino-2,4,6-trideoxysugar stereoisomers in 6-7 steps and 22-33% overall yield is described. A key step in this pathway is the carbonyl coupling of d- and l-threoninol or d- and l-allo-threoninol to a phthalimido-allene mediated by chiral iridium-H8-BINAP, which allows for installation of two new chiral centers in one, highly diastereoselective (>20:1 dr) step. This approach provides a more concise, diastereoselective, and versatile method to access these deoxy-amino sugars than is currently available.