Koenigs-Knorr route

This synthesis is very stereoselective with less than 5 % of the a anomer in the alkyl D-glucoside finally produced. Unfortunately, because of the steps needed and the selectivity in each step the final yield is below 50 %, irrespective of the aliphatic alcohol used [8]. 

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Another total synthesis of ribostamycin (363), a broad-spectrum antimicrobial antibiotic produced by Streptomyces ribosidificus, has been reported. The synthetic route involved the condensation of a suitably protected S-O- -d-ribofuranosyl-2-deoxystreptamine derivative with 3,4-di-0-acetyl-2,6-dideoxy-2-(2,4-dinitroanilino)-6-phthalimido-a-D-gIucopyranosyl bromide under modified Koenigs-Knorr conditions. A standard Koenigs-Knorr reaction has been used... 

With the objective of reducing the formation of oligoglucosides and also to control the stereoselectivity, Koenigs and Knorr [8] developed another route which involves protection of the hydroxyls in the sugar [9-11]. 

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