title: Highly efficient photochemically induced thiyl radical-mediated racemization of aliphatic amines at 30 degrees C.
abstract: UV irradiation in the presence of thiol enables the performance of highly efficient aliphatic amines racemization, under mild conditions at 30 degrees C. The reaction proceeds via the reversible generation of prochiral alpha-aminoalkyl radicals. The latter may result either from a redox process between the thiyl radical and the amine or from direct hydrogen atom abstraction by thiyl radical. As hydrogen atom donor, the thiol plays a crucial role. While the racemization of both primary and secondary amines were fast processes, the racemization of tertiary amines was sluggish. A tentative rationale is based on the photostimulated amine-catalyzed oxidation of the thiol into the corresponding disulfide, which makes the hydrogen atom donor concentration in the reaction medium drop up to trace amount at a rate that depends on the nature of the amine.
authors: Laboratoire de Chimie Moléculaire Organique, UMR 6517, Chimie, Biologie, et Radicaux Libres, Boite 562, Université Paul Cézanne, Aix-Marseille III, Faculté des Sciences St Jérôme, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France.
authors: Lucie
authors: L
authors: Routaboul
authors: Nicolas
authors: N
authors: Vanthuyne
authors: Stéphane
authors: S
authors: Gastaldi
authors: Gérard
authors: G
authors: Gil
authors: Michèle
authors: M
authors: Bertrand
mesh_terms: D000588:Amines / Q000737:chemistry* / Q000528:radiation effects; D005609:Free Radicals / Q000737:chemistry / Q000528:radiation effects; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010777:Photochemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D000588:Amines; D005609:Free Radicals; D013438:Sulfhydryl Compounds