Elucidation of the acid reactivity of polyhedral orthoformates for the synthesis of carbasugar derivatives

Carbasugar-containing natural products such as uvaridacol L have a variety of bioactivities, motivating chemists to develop methods for their synthesis. The conversion of <i>myo</i>-inositol is one of the most efficient methods for the synthesis of carbasugars. However, selective conversion of <i>myo</i>-inositol derivatives remains to be explored. In our synthesis of uvaridacol L derivatives, we found that the methoxy olefin derivatives of orthoester-protected <i>myo</i>-inositols, the key synthetic intermediates of our study, exhibit differing reaction selectivities depending on their geometric isomerism and substituents. Here we present new insights that contribute to the synthesis of carbasugar-type derivatives by elucidating the mechanism of the selectivity using density functional theory (DFT) calculations.