Introduction of Vinyl and Hydroxymethyl Functionalities at C-4 of Glucose-Derived Substrates: Synthesis of Spirocyclic, Bicyclic, and Tricyclic Nucleosides

Installing hydroxymethyl and hydroxyethyl substitutions at C-4 through vinylation and hydroboration−oxidation reactions of the C-4 bis-hydroxymethyl derivative of d-glucose based substrate, and inserting heteroatoms thereafter permitted formation of N-, O-, or S-heterocycles leading to [4,5]- or [5,5]-spirocycles and a bicyclo[3.3.0]octane product. Some of the spirocycles were converted to spironucleosides under Vorbrüggen glycosidation reaction conditions. Similarly, the bicyclic product was elaborated to the corresponding bicyclic nucleoside as well as an unexpected tricyclic nucleoside.