Editorial: Recent advances in carbohydrate chemical and enzymatic syntheses

It is now widely accepted that oligosaccharides and glycoconjugates play a host of critical 11 roles in biological processes, including cell adhesion, signaling, and the immune response (Varki). 12 This has led to increased recognition that glycoconjugates with unusual glycosylation patterns hold 13 enormous potential for developing vaccines against a variety of diseases ranging from pathogens to 14 cancer (Astronomo, Berti). Even free oligosaccharides have been shown to possess potent 15 bioactivity such as the antimicrobial activity of human milk oligosaccharides (HMOs) (Craft) and the 16 myriad of roles that heparan sulfate plays in cell-cell interactions (Chhabra). Furthermore, the 17 alteration of carbohydrates on natural products can dramatically alter their activity, a process known 18 as glycodiversification (Elshahawi). We believe that the work described in this Research Topic nicely highlights some of the 60 current challenges and progress that exist in the field of carbohydrate chemistry. It is our hope that 61 this work will encourage other chemists to toss their own hat into this exciting and rapidly growing 62 field, where there are many more discoveries to be made. 63