Chiral Ligands Based on Binaphthyl Scaffolds for Pd-Catalyzed Enantioselective C-H Activation/Cycloaddition Reactions
José Manuel González1, Xandro Vidal1, Manuel Angel Ortuño1
1Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Abstract:
We report the first examples of the use of a new class of ligands (NOBINAc) for performing asymmetric C-H activations using palladium catalysts. These ligands combine the axial chirality of binaphthyl scaffolds with the bifunctional and bidentate coordination properties of mono-N-protected amino acids (MPAAs), which are well-known to favor Pd-promoted C-H activations via concerted metalation-deprotonation mechanisms. We demonstrate that our new ligands enable substantially higher enantioselectivities than MPAAs in the assembly of 2-benzazepines through formal (5 + 2) cycloadditions between homobenzyltriflamides or o-methylbenzyltriflamides and allenes.
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