Editing Glycosidic bond (section)

=== Vishal Y Joshi's method ===

Joshi et al. (2006)<ref>{{cite journal | vauthors =Joshi VY, Sawant MR | year = 2006 | title = A convenient stereoselective synthesis of β-D-glucopyranosides | journal = Indian Journal of Chemistry | volume = 45B | pages = 461–465 }}</ref> propose the [[Koenigs-Knorr reaction]] in the stereoselective synthesis of alkyl D-glucopyranosides via glycosylation, with the exception of using [[lithium carbonate]] which is less expensive and toxic than the conventional method of using [[silver]] or [[Mercury (element)|mercury]] salts. D-glucose is first protected by forming the [[peracetate]] by addition of [[acetic anhydride]] in [[acetic acid]], and then addition of [[hydrogen bromide]] which brominates at the 5-position. On addition of the alcohol ROH and lithium carbonate, the OR replaces the bromine and on deprotecting the acetylated hydroxyls the product is synthesized in relatively high purity. It was suggested by Joshi et al. (2001) that lithium acts as the nucleophile that attacks the carbon at the 5-position and through a [[transition state]] the alcohol is substituted for the bromine group. Advantages of this method as well as its stereoselectivity and low cost of the lithium salt include that it can be done at room temperature and its yield compares relatively well with the conventional Koenigs-Knorr method.<ref>{{cite journal | vauthors = Koenigs W, Knorr E | date = 1901 | title = Ueber einige Derivate des Traubenzuckers und der Galactose | journal = Berichte der Deutschen Chemischen Gesellschaft | volume = 34 | issue = 1 | pages = 957–981 | doi = 10.1002/cber.190103401162 | url = https://zenodo.org/record/1425998 }}</ref>[[File:Vishal Joshi.png|thumb]]