H. Tavakol and S. Zakery, Synthesis of α-Cyanohydroxylamines from Aldehydes  13^th Iranian seminar of Organic Chemistry, Bu-Ali Sina University, Hamedan, Iran, 6-8 September 2006

Abstract

α-Cyanohydroxylamines [1] very important compound in organic chemistry because they are useful intermediates in synthesis of  α-amino acids. Therefore, synthesis of these compounds have been challenged organic chemists of world for long time. For preparation of these compounds, we can use the strecker-type synthesis via addition of cyanide nucleophile to electrophilic carbon of C=N double bond in oximes or oximethers [2]. This method is useful but limited to some conditions because of poor electrophilicity of oximes [3] (versus carbonyl group), tutomeric conversion of substrate that contains
α-Hydrogen to enamine-type product, existence of geometric isomerisation (syn and anti), liability of N-O bond, possibility of addition to both carbon and nitrogen in C=N double bond, and formation of byproducts such as aziridine, nitrile, and Beckmann rearrangement products [4]. So that, it is very important that one procedure can produce only one of these products in high yield without major formation of other byproducts. In our researches, we succeeded at completing this reaction with very high yield at room temperature by using lithiumperchlorate as a lewis acid in diethyl ether solution. The key of this success is coordinating the nitrogen of oxime to lithiumperchlorate that it not only caused the coordinated C=N double bond to be high electrophilic than ordinary C=N double bond, but also this prevent other unwanted side reactions and synthesis of other byproducts. In the below scheme we see the common reaction of this synthesis.