4-Azido-3-chlorobenzyl Ether, New Protection for Hydroxy Functions

Abstract
The 4-azido-3-chlorobenzyl (Cl-Azb) group was readily introduced to hydroxy functions by the use of a crystalline reagent, 4-azido-3-chlorobenzyl bromide, which was prepared from commercially available 2-chloro-4-methylaniline in two steps. Cl-Azb ethers have improved acid stability as compared to the corresponding parent 4-azidobenzyl (Azb) ether. Cl-Azb ethers were stable to direct 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) oxidation, but were cleaved smoothly by DDQ oxidation after conversion to the corresponding iminophosphorane derivative.