Diamination of Olefins: Synthesis, Structures and Reactivity of Osmaimidazolidines

• Published in: Chemistry : a European journal Vol. 9; no. 22; pp. 5581 - 5596
• Main Authors: Muñiz, Kilian, Iesato, Atsushi, Nieger, Martin
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 21.11.2003; WILEY‐VCH Verlag; Wiley
• Subjects: Chemistry; Chemistry, Multidisciplinary; diamination; osmium; Physical Sciences; Science & Technology; stereoselective synthesis; transition-metal complexes; BETA-AMINO ESTERS; CATALYZED ASYMMETRIC DIHYDROXYLATION; MOLECULAR-STRUCTURE; osmium; diamination; MAIN-GROUP ELEMENTS; TRANSITION-METALS; STEREOSPECIFIC VICINAL OXYAMINATION; stereoselective synthesis; OSMIUM IMIDO COMPLEXES; X-RAY CRYSTAL; HIGHLY ENANTIOSELECTIVE DIHYDROXYLATION; MULTIPLE BONDS; transition-metal complexes
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200305011

The diamination of certain olefins bearing electron‐withdrawing substituents proceeds with well‐defined bisimido and trisimido complexes of osmium. The products are obtained as osmaimidazolidines which are of unprecedented stability with regards to olefin functionalisation. Osmium complexes from related dihydroxylation or aminohydroxylation are significantly less stable and thereby promote catalytic reactions. This difference in reaction profile has been investigated and chiral osmium heterocycles obtained from olefin difunctionalisation were characterised by X‐ray analysis for the first time. Kinetic studies on the reaction profile have also been carried out. An asymmetric version of this reaction is based on chiral non‐racemic auxiliaries and leads to diastereomerically enriched osmaimidazolidines with up to 90 % de. This sequence represents the first asymmetric diamination of olefins. Attempts on the use of chiral ligands for direct asymmetric diamination as well as the consequences of osmaimidazolidine properties for a catalytic reaction are discussed. The direct diamination of unsymmetrically substituted olefins (see scheme) leads to chiral osmaimidazolidine products with unprecedented stability. The nature of these compounds has been studied in detail and several important differences regarding related osmium chemistry have been determined. A first asymmetric diamination of olefins is based on this reaction sequence which gives diastereomerically enriched osmaimidazolidines with up to 90 % de.