2-Amino ketones from osmium-catalysed oxidations of alkenes

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 2006-05, Vol.251 (1), p.277-285
• Main Authors: Muñiz, Kilian, Hövelmann, Claas H., Villar, Amparo, Vicente, Rubén, Streuff, Jan, Nieger, Martin
• Format: Article
• Language: English
• Subjects: Alkenes; Amino ketones; Aminohydroxylation; Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Osmium; Oxidation; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2006.02.013

The first examples of direct conversion of alkenes to yield racemic 2-amino ketone products in what represents a so-far unknown reactivity in osmium catalysis are presented. In addition, a two-step procedure, which converts alkenes into enantiomerically pure vicinal amino alcohols followed by stereoselective oxidative conversion into 2-amino ketones is described. Both pathways derive from a common mechanistic background and constitute a novel side-reaction of the original aminohydroxylation chemistry. ▪ The present article summarises imidoosmium-catalysed oxidations of alkenes to yield 2-amino ketones. Three different approaches are discussed. The first section describes the direct conversion of alkenes to yield racemic 2-amino ketone products in what represents a so-far unknown reactivity in osmium catalysis. It is followed by the description of a two-step procedure, which converts alkenes into enantiomerically pure vicinal amino alcohols followed by stereoselective oxidative conversion into 2-amino ketones. Both pathways derive from a common mechanistic background and constitute a novel side-reaction of the original aminohydroxylation chemistry. An alternative synthetic approach of osmium-catalysed aminohydroxylation of silyl enol ethers is discussed as well and is compared to the previous two procedures.