Sodium Borohydride Reactions under Phase-Transfer Conditions: Reduction of Azides to Amines

Article abstract of DOI:10.1021/jo00143a031

Under phase-transfer catalysis (PTC) conditions organic azides are reduced to amines in high yields by aqueous sodium borohydride: aryl and arylsulfonyl azides give the corresponding amino derivatives at room temperature, while alkyl azides require more drastic conditions (80 deg C). tert-Butyl 2-azido-2-phenylacetate, after reduction at room temperature and acidic workup, gives phenylglycine in a 72percent overall yield.The PTC technique allows the conversion of alkyl chlorides, bromides, and methanesulfonates into pure primary amines via a one-pot procedure by reacting a mixture of the substrate and a PTC agent first with aqueous NaN3 and then with aqueous NaBH4.