O-(Diphenylphosphinyl)hydroxylamine

Abstract

(A) The direct amination of stabilized enolates or enolate-like compounds can be achieved in good to excellent yields using 1.5 The more stabilized the carbanion is, the higher is the achieved yield. Depending on the steric hindrance of substrates, chirality may be introduced.6 An obvious application is the synthesis of amino acids.7 B) The stabilization of carbanions by conjugate systems as aryls or olefins allows their amination by 1. The cyclopentadiene derivatives obtained are often used in stereoselective Diels-Alder reactions.8 (C) The electrophilic amination of lithium diene- and trienediolate of unsaturated carboxylic acids leads to useful unsaturated amino acids. The amination occurs selectively at the α-carbon. The moderate yields are induced by the difficult isolation of this kind of amino acids due to their well-known instability.9 (D) Access to a wide range of primary amines is easily provided starting from the corresponding halogen derivatives by an Umpolung strategy. The amination yield increases in the order RMgBr < RMgCl.14 (E) A highly efficient metal-free strategy to synthesize hydrazines from secondary amines bearing an electron-withdrawing group can be carried out using 1.10 If the substrate is a primary amine protected by a Boc group, a monosubstituted hydrazine can be synthesized in only two steps. (F) Electrophilic N-amination of aromatic π-electron-rich nitrogen heterocycles occurs in high yields. 3,11 It often represents the key step of the synthesis of variously substituted bicycles. For example, they can be easily obtained by heating the hydrazine derivatives in a sealed tube in the presence of formamide. 12 (G) Compound 1 may furnish ammonium salts from tertiary amines.13 Ammonium salts can be very interesting reagents for further reactions (cf. H). (H) A novel efficient method for the aziridination of a large range of enone systems uses a key reagent prepared in situ by N-amination of a tertiary amine.14 © Thieme Stuttgart.