Access to Rare <scp>d</scp> - and <scp>l</scp> -Hexoses from C1 Nucleophiles via Anomeric Acylation

We report a stereoretentive homologation of C1 anomeric nucleophiles into C1 esters produced in both anomeric configurations, starting from configurationally stable anomeric stannanes and boronic acids. This reaction enabled elaboration of the homologated structure in both anomeric configurations into the respective l-hexoses starting from the β anomers of d-hexoses, whereas the α anomer of the d-hexoses produces the d-series of rare sugars such as d-gulose and d-idose.