Acyloxonium ions in the high-yielding synthesis of oxolanes from alditols, hexoses, and hexonolactones catalysed by carboxylic acids in anhydrous hydrogen fluoride

Article abstract of DOI:10.1016/0008-6215(90)80139-T

Treatment of D-glucono-1,5- or D-mannono-1,4-lactone with anhydrous hydrogen fluoride catalysed by formic or acetic acid yields 3,6-anhydro-D-glucono- and -D-mannono-1,4-lactone, respectively.Similarly, D-mannitol is converted into 1,4-anhydro-D-mannitol and subsequently into the 1,4:3,6-dianhydride, whereas D-glucitol forms exclusively the 3,6-anhydride and, on further reaction, 1,4:3,6-dianhydro-D-glucitol.D-Glucose and 2-acetamido-2-deoxy-D-glucose are also converted into the corresponding 3,6-anhydrides by reaction with hydrogen fluoride and formic acid.13C-N.m.r. spectroscopy indicates that the reactions involve intermediate dioxolanyium ions.