Regioselective Protection at the Secondary Positions of Carbohydrates with Acyclic Protecting Groups
Résumé
The regioselective protection of secondary alcohols of carbohydrates such as hexopyranoside 2,3-diols, 2,3,4-triols, and 2,3,4,6-tetraols is compiled and discussed with ethers (silyl, benzyl, and allyl), methoxymethyl acetals, and esters (acetyl and benzoyl). The regioselective double protection of 2,3,4,6-tetraols is also covered. Finally, the regioselective mono-deprotection of one of the secondary positions of tetrasubstituted glycosides provides an efficient route to carbohydrate precursors having the 2-, 3-, or 4-position differentiated.