RESUMO
The work being reported here deals with the design of a new type of "N-H" Ni(II) complexes of glycine Schiff bases and study general aspects of their reactivity. It was confirmed that the presence of NH function in these Ni(II) complexes does not interfere with the homologation of the glycine residue, rendering these derivatives of high synthetic value for the general synthesis of α-amino acids. In particular, the practical application of these NH-type complexes was demonstrated by asymmetric synthesis of various ß-substituted pyroglutamic acids via Michael addition reactions with chiral Michael acceptors.
Assuntos
Complexos de Coordenação/química , Glicina/química , Níquel/química , Bases de Schiff/química , Cristalografia por Raios X , Modelos Moleculares , Ácido Pirrolidonocarboxílico/química , EstereoisomerismoRESUMO
Two birds, one stone! The first kinetic resolution of allyl fluorides was achieved by the development of an organocatalyzed enantioselective allylic trifluoromethylation. Two kinds of chiral fluorinated compounds, which incorporate C*F and C*CF3 units, respectively, can thus be accessed by a single transformation.
Assuntos
Compostos Alílicos/síntese química , Carbono/química , Fluoretos/química , Hidrocarbonetos Fluorados/síntese química , Compostos de Organossilício/química , Compostos Alílicos/química , Catálise , Hidrocarbonetos Fluorados/química , Cinética , Metilação , Estrutura Molecular , EstereoisomerismoRESUMO
Allyl carbonates undergo palladium-catalyzed decarboxylative allylation of trifluoroethyl phenyl sulfones. The success of the allylation, which is not efficient under typical strong base-mediated conditions, is the result of mild conditions thanks to a progressive delivery of ethoxide. Indeed, ethyl allyl carbonates act as a latent source of ethoxide for generation of the trifluoroethyl carbanion that reacts with the π-allylpalladium complex. The utility of the method is illustrated in a new approach to difluoromethyl compounds.