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Electrophilic Amination of C-H-Acidic Compounds with 1-Oxa-2-azaspirooctane
Andreae, Siegfried,Schmitz, Ernst,Wulf, Jens-Peter,Schulz, Burkhard
, p. 239 - 256 (2007/10/02)
The reactions of 1-oxa-2-azaspirooctane (1, 3,3-pentamethyleneoxaziridine) with malonic (e. g. 4, 35) and cyanoacetic acid derivatives (e. g. 11, 13, 20) and other C-H acids have been studied.After the introduction of a 1-hydroxycyclohexylamino group at the acidic position, five different stabilisation reactions of the intermediate 2 could be classified.The most important one is an intramolecular nucleophilic attack to a nitrile group giving disubstituted 1,4-diazaspiro decanones 2a.Their ring transformations (e. g. 2a -> 3) or the introduction of a second amino group at the same carbon atom (2a -> 3a) are further new reactions.Geminal diamino acid derivatives 3a thus obtained can be stable or rearrange to 3 (R1 = NH2) or eliminate cyclohexanone (formation of 42) and/or ammonia (formation of 41 or 43).Amination of N-cyanoacetyl-protected amino acid esters (20, NHR = amino acid unit) with 1 yields cyclic dipeptide derivatives 41. Key Words: 1-Oxa-2-azaspirooctane / C-H acids / Electrophilic amination / Diamination / Amino acid derivatives / Dehydro peptides
