Streamlined access to carbohydrate building blocks: Methyl 2,4,6-tri-O-benzyl-α-d-glucopyranoside

Presented herein is an improved synthesis of a common 3-OH  glycosyl  acceptor. This compound is a building block that is routinely synthesized by many research groups to be used in  glycosylation  refinement studies. The only known direct synthesis by Koto lacks  regioselectivity  and relies on  chromatography  separation using hazardous solvents. Our improved synthetic approach relies on Koto's selective  benzylation  protocol, but it is followed by acylation-purification-deacylation sequence. Although this approach involves additional manipulations, it provides consistent results and is superior to other indirect strategies. Also obtained, albeit in minor quantities, is 4-OH acceptor, another common building block.