H. Tavakol and A. Heydari, Preparation of various hydroxylamines in three component aminoreduction reaction  12^th Iranian seminar of Organic Chemistry, Ahwaz jundi shapour university of medical science, Ahwaz, Iran, 7-9 March 2006

Abstract

Multi-component reactions (MCRs) are of special type in synthetic organic chemistry, in which three or more starting materials react to give one product [1]. Among these, the Mannich reaction (M-3CR) [2], where an amino methyl group is introduced in the α-position to a carbonyl function, has found a multitude of applications. Examples include: Michael acceptors and β-amino alcohols [3]. In addition, Mannich or Mannich-type reactions have been widely used for the synthesis of many biologically attractive molecules [4]. Also a powerful tool for the synthesis of substituted amines is the Mannich-type reductive amination of carbonyl groups [5] and we can use this reaction for preparation of hydroxylamines. This synthesis involves the formation of an oximes followed by in situ reduction. This approach is highly practiced for rapid access to a diverse set of hydroxylamines due to the wide choice of starting carbonyl compounds. Nevertheless, reductive alkylation reactions are particularly prone to a high degree of overalkylation [6]. Consequently, finding a robust general procedure for selective preparation of monosubstituted hydroxylamines is an important objective in organic synthesis. In this paper we wish to report a mild, simple and efficient conversion of aldehydes to monosubstituted hydroxylamines in LPDE medium. In this reaction an trimethylsilyloximeether, formed in situ by the mixture of aldehyde and O-trimethylsilyl hydroxylamine, is submitted to a reduction by Boran-Triethylamine/Trimethylsilylchloride (Scheme 1). in all cases, the desired products were obtained in high yields.