title: Gold catalysis: 1,3-oxazines by cyclisation of allene amides.
abstract: A series of allene amides was prepared and their gold-catalysed cyclisation was investigated. The formation of six-membered rings, 1,3-oxazines, was observed. Dihydropyrroles originating from intramolecular hydroamination of the distal C=C double bonds of the allenes were minor side products. Mechanistic studies by in situ (31)P NMR spectroscopy showed only one additional species during the conversion in each case; a computational study of the different allyl gold(I) species involved allowed this to be assigned as the σ-allyl gold species bearing the gold catalyst at the sterically less hindered methylene end. The regiospecific deuterodeauration of this intermediate confirmed a S(E) '-type mechanism for this last step of the catalytic cycle.
authors.affiliation: Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany. hashmi@hashmi.de
authors.forename: A Stephen K
authors.initials: AS
authors.lastname: Hashmi
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Schuster
authors.forename: Sebastian
authors.initials: S
authors.lastname: Litters
authors.forename: Frank
authors.initials: F
authors.lastname: Rominger
authors.forename: Markus
authors.initials: M
authors.lastname: Pernpointner