Diazoaldehyde Chemistry. Part 1. Transdiazotization of Acylacetaldehydes in Neutral-to-Acidic Medium. A Direct Approach to the Synthesis of α-Diazo-β-oxoaldehydes
✍ Scribed by Özkan Sezer; Olcay Anaç
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- German
- Weight
- 708 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
First ever non‐deformylating transdiazotization of acylacetaldehydes was achieved: the reactions of 2‐azido‐l‐ethylpyridinium tetrafluoroborate (4) with acylacetaldehydes 3 proceeded partially without deformylation to yield 16 new α‐diazo‐β‐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. α‐Oxocycloalkanecarbaldehydes 5 gave only traces (if any) of α‐diazocycloalkanones 7, and rearrangement products 6 were isolated (Scheme 2). Mechanisms of the reactions are discussed (Schemes 4 and 5).