DIAZOALDEHYDE CHEMISTRY .1. TRANSDIAZOTIZATION OF ACYLACETALDEHYDES IN NEUTRAL-TO-ACIDIC MEDIUM - A DIRECT APPROACH TO THE SYNTHESIS OF ALPHA-DIAZO-BETA-OXOALDEHYDES)


SEZER O. , ANAC O.

HELVETICA CHIMICA ACTA, vol.77, no.8, pp.2323-2334, 1994 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 77 Issue: 8
  • Publication Date: 1994
  • Doi Number: 10.1002/hlca.19940770819
  • Title of Journal : HELVETICA CHIMICA ACTA
  • Page Numbers: pp.2323-2334

Abstract

First ever non-deformylating transdiazotization of acylacetaldehydes was achieved: the reactions of 2-azido-1-ethylpyridinium tetrafluoroborate (4) with acylacetaldehydes 3 proceeded partially without deformylation to yield 16 new alpha-diazo-beta-oxoaldehydes 1 along with diazomethyl ketones 2, especially in the presence of NaOAc (Scheme 1, Tables 1 and 2). The product distribution was substituent-dependent and could be correlated quantitatively. This new diazotization reaction appears as an alternative, direct, and more general method for the synthesis of these diazooxoaldehydes. alpha-Oxocycloalkanecarbaldehydes 5 gave only traces (if any) of alpha-diazocycloalkanones 7, and rearrangement products 6 were isolated (Scheme 2). Mechanisms of the reactions are discussed (Schemes 4 and 5).