Site-Selective Photobromination of O -Acetylated Carbohydrates in Benzotrifluoride.

Ferrier photobromination enables direct synthetic access to valuable 5- C -bromosugars but has limitations that restrict its broader use. The reaction is typically conducted in CCl 4 heated at reflux with irradiation by broad spectrum, energy-inefficient heat lamps. Herein, we demonstrate that the reaction proceeds rapidly and efficiently with PhCF 3 as a safe and environmentally benign alternative to CCl 4 at mild temperatures (≤40 °C) inside a compact photoreactor fitted with purple light-emitting diodes (LEDs).