Carbohydrates are essential in various biological functions and disease processes, and glycosidic linkages are found in all living organisms. However, stereoselective glycosylation remains a significant challenge in glycoscience and organic chemistry, limiting the study of carbohydrates due to their structural complexity. SN1 or SN2-type reactivity is utilized in most glycosylation approaches, which are dominated by anomeric effects and protecting group manipulation. While some catalytic methods exist, they use precious metals (rhodium/gold/palladium) to achieve the desired stereoselectivity. In response to these challenges, a carbene-based glycosylation approach has been developed to form various glycosidic linkages, including challenging 1,2-cis-glycosides, 1,2-cis-furanosides, β-2-deoxy glycosides, and α-sialosides. This chemistry utilizes Earth-abundant metals (Fe/Cu/Zn) as catalysts or metal-free, blue-LED conditions. This method works with an array of nucleophiles (O, N, S, and C) and achieves high desired stereoselectivity at the anomeric position without protecting group manipulation or anchimeric assistance. This represents a significant advancement over traditional glycosylation methods. The carbene chemistry has also been utilized to access a practical economic synthesis of sialic acid (Neu5Ac) and analogs (KDO/KDN) from commercially available carbohydrates. In collaboration with the Zgurskaya group (OU), glycosylation of identified benzenesulfonamide (BSA) hits for Pseudomonas aeruginosa will help overcome the permeation barrier and expand our knowledge of molecular interactions with cell-surface molecules in Gram-negative bacteria.
Recent Publications: 
ACS Catal. 2024, 14, 1037–1049 DOI: 10.1021/acscatal.3c05237
Adv. Synth. Catal. 2024 DOI: 10.1002/adsc.202301207
Org. Lett. 2024, 26, 9436-9441 DOI: 10.1021/acs.orglett.4c03281
Molecules 2024, 29(22), 5367 DOI: 10.3390/molecules29225367