title: Mechanism of gold(I)-catalyzed rearrangements of acetylenic amine-N-oxides: computational investigations lead to a new mechanism confirmed by experiment.
abstract: Quantum mechanical studies of the mechanism of gold-catalyzed rearrangements of acetylenic amine-N-oxides to piperidinones or azepanones have revealed a new mechanism involving a concerted heteroretroene reaction, formally a 1,5 hydrogen shift from the N-alkyl groups to the vinyl position of a gold-coordinated methyleneisoxazolidinium or methyleneoxazinanium. Density functional calculations (B3LYP, B3LYP-D3) on the heteroretroene mechanism reproduce experimental regioselectivities and provide an explanation as to why the hydrogen is transferred from the smaller amine substituent. In support of the proposed mechanism, new experimental investigations show that the hydrogen shift is concerted and that gold carbenes are not involved as reaction intermediates.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Noey
authors.forename: Yingdong
authors.initials: Y
authors.lastname: Luo
authors.forename: Liming
authors.initials: L
authors.lastname: Zhang
authors.forename: K N
authors.initials: KN
authors.lastname: Houk
mesh_terms: D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D003198:Computer Simulation; D006046:Gold / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D010087:Oxides / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000588:Amines; D010087:Oxides; D006046:Gold