The direct azidation of various heterocyclic beta-ketoesters, lactones, and lactams is reported. By using tosylazide and an organic base such as L-proline or TBD, the direct alpha-insertion of azide into these substrates was achieved in moderate to good yields, without competitive deacylating diazo transfer. This procedure represents an interesting alternative to the usual two-step approach of alpha-halogenation and subsequent displacement with azide ion. (C) 2009 Elsevier Ltd. All rights reserved.
The direct azidation of various heterocyclic beta-ketoesters, lactones, and lactams is reported. By using tosylazide and an organic base such as L-proline or TBD, the direct alpha-insertion of azide into these substrates was achieved in moderate to good yields, without competitive deacylating diazo transfer. This procedure represents an interesting alternative to the usual two-step approach of alpha-halogenation and subsequent displacement with azide ion. (C) 2009 Elsevier Ltd. All rights reserved.