Details

Autor(en) / Beteiligte

• D'hooghe, Matthias
• Catak, Saron
• Stanković, Sonja
• Waroquier, Michel
• Kim, Yongeun
• Ha, Hyun-Joon
• Van Speybroeck, Veronique
• De Kimpe, Norbert

Titel

Systematic Study of Halide-Induced Ring Opening of 2-Substituted Aziridinium Salts and Theoretical Rationalization of the Reaction Pathways

Ist Teil von

• European Journal of Organic Chemistry, 2010-09, Vol.2010 (25), p.4920-4931

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2010

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The ring‐opening reactions of 2‐alkyl‐substituted 1,1‐bis(arylmethyl)‐ and 1‐methyl‐1‐(1‐phenylethyl)aziridinium salts with fluoride, chloride, bromide and iodide in acetonitrile have been evaluated for the first time in a systematic way. The reactions with fluoride afforded regioisomeric mixtures of primary and secondary fluorides, whereas secondary β‐chloro, β‐bromo and β‐iodo amines were obtained as the sole reaction products from the corresponding halides by regiospecific ring opening at the substituted position. Both experimental and computational results revealed that the reaction outcomes in the cases of chloride, bromide and iodide were dictated by product stability through thermodynamic control involving rearrangement of the initially formed primary halides to the more stable secondary halides. The ring opening of the same aziridinium salts with fluoride, however, was shown to be mediated by steric interactions (kinetic control), with the corresponding primary β‐fluoro amines being obtained as the main reaction products. Only for 2‐acylaziridinium ions was the reaction outcome shown to be under full substrate control, affording secondary β‐fluoro, β‐chloro, β‐bromo and β‐iodo amines through exclusive attack at the activated α‐carbonyl carbon atom. The ring opening of 2‐alkyl‐substituted aziridinium salts with chloride, bromide and iodide proceeds under thermodynamic control with product stabilities dictating theoutcome of the reactions. Fluoride‐mediated ring opening, however, proceeds under kinetic control, the reaction outcome being dictated only by steric interactions.