Benzylated glycosyl formates have been synthesized in one step from the corresponding hemiacetal or orthoester with formic acid as the sole reagent. The glycosyl formates are used as glycosyl donors under catalytic conditions with cheap metal catalysts based on iron or bismuth. A 13C NMR spectroscopic method is developed and evaluated for screening reactions conditions, giving precise information on the selectivity, yield, and byproducts formed. The major side reaction is transesterification, which gives the formylated acceptor and regenerates the hemiacetal. By using this approach, catalyst loadings and solvents are optimized and the scope of the glycosylation is evaluated for a variety of glycosyl donors and acceptors. A proof of concept for a traceless glycosylation, utilizing a dual‐purpose iron catalyst that catalyzes both glycosylation and dehydrogenation of formic acid, is also provided.

Novel bicyclic d‐galactose derivatives containing a molecular lever were synthesized and their conformations studied by 1H‐NMR and crystallography. Increasing the bulkiness in the alkylidene ring in combination with introducing bulky O‐protective groups on the pyranoside ring, causes a ring flip from a 4C1 into the axial rich 1C4 conformation. With less bulky protective groups, the pyranoside ring resides in the 4C1 conformation despite distortion of the external alkylidene ring.