An efficient method for the synthesis of pyranoid glycals

A simple and efficient procedure was designed for the preparation of pyranoid glycals. In a novel fashion, a series of protected glycopyranosyl bromides underwent reductive elimination in the presence of zinc dust and ammonium chloride in CH3CN at 30–60 °C. The corresponding glycals were obtained with excellent isolated yields (72–96%) in a short time (20–50 min). Furthermore, the transformation was compatible with different protection patterns and conveniently scalable (86% for 45 g acetobromoglucose) which made it very applicable in organic synthesis. [Display omitted] •Synthesis of pyranoid glycals using Zn/NH4Cl system.•High yields and short reaction time.•Simple operation and broad functional group compatibility.•Efficient synthesis of glucal in gram-scale amount.