Photolabile ortho‐Nitro‐Benzyl Carbonate as an Amino Protecting Group for Stereocontrolled Synthesis of 2‐Amino‐2‐Deoxy‐β‐D‐Glycosides

Abstract

Traditional amino protecting groups are often removed under harsh conditions or incompatible with other protecting groups, rendering the synthesis of complex 2‐amino‐2‐deoxy‐β‐D‐glycosides difficult. Here, we utilize the photolabile ortho‐nitrobenzyl carbonate (oNBC) as an amino protecting group for stereocontrolled synthesis of 2‐amino‐2‐deoxy‐β‐D‐glycosides. The gold(I)‐catalyzed glycosylation with per‐O‐oNBC‐protected 2‐N‐phthaloyl (Phth)‐2‐deoxy‐, 2‐N‐trichloroacetyl (TCA)‐2‐deoxy‐, and 2‐N‐oNBC‐2‐deoxy‐glycosyl ynenoates proceeded smoothly to provide 2‐amino‐2‐deoxy glycosides with exclusive β‐selectivities via the neighboring group participation (NGP) effect. Removal of the multiple O‐ and N‐oNBC protecting groups of 2‐amino‐2‐deoxy glycosides was achieved under irradiation at 365 nm with aminomethyl polystyrene as the carbonyl scavenger.