Site-Selective Photobromination of O-Acetylated Carbohydrates in Benzotrifluoride

Abstract

The Ferrier photobromination enables direct synthetic access to valuable 5-C-bromosugars but has limitations which restrict its broader use. The reaction is typically conducted in CCl4 heated at reflux with irradiation by broad spectrum, energy inefficient heat lamps. Herein, we demonstrate that the reaction proceeds rapidly and efficiently with PhCF3 as a safe and environmentally benign alternative to CCl4 at mild temperatures (≤ 40 °C) inside a compact photoreactor fitted with purple LEDs.