Synfacts 2011(1): 0101-0101  
DOI: 10.1055/s-0030-1259190
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart ˙ New York

γ-Alkylation of α-Branched Enals with Stable Carbocations

Contributor(s): Benjamin List, Lars Ratjen
G. Bergonzini, S. Vera, P. Melchiorre*
Institució Catalana de Recerca i Estudis Avançats, Barcelona and Institute of Chemical Research of Catalonia, Tarragona, Spain
Weitere Informationen


21. Dezember 2010 (online)


The asymmetric vinylogous γ-alkyl­ation of α-branched enals with bis-(4-dimethyl­aminophenyl)-methanol is reported. The catalyst involves cinchona alkaloid derived primary amine 1, in combination with chiral phosphoric acid 2, setting the stage for a cooperative mechanism. The catalyst salt formed between 1 and one equivalent of chiral phosphoric acids, is believed to deliver a dienamine, which reacts with the benz-hydryl cation through a highly ordered transition state.