Palladium(II)-Catalyzed Annulation betweenortho-Alkenylphenols and Allenes. Key Role of the Metal Geometry in Determining the Reaction Outcome.
2-Alkenylphenols react with allenes, upon treatment with catalytic amounts of Pd(II) and Cu(II), to give benzoxepine products in high yields and with very good regio- and diastereoselectivities. This contrasts with the results obtained with Rh catalysts, which provided chromene-like products through a pathway involving a β-hydrogen elimination step. Computational studies suggest that the square planar geometry of the palladium is critical to favor the reductive elimination process required for the formation of the oxepine products.
Centro 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.
Noelia
N
Casanova
Centro 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.
Karina P
KP
Del Rio
Centro 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.
Rebeca
R
García-Fandiño
Centro 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.
José L
JL
Mascareñas
Centro 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.
Moisés
M
Gulías
C−H activation; allene; cycloaddition; oxepine; palladium