An efficient and highly enantioselective Michael addition of nitroalkanes to 3-ylidene oxindoles is described, mediated by thiourea-based bifunctional organocatalysts. The stereochemistry at C-alpha and C-beta centers is perfectly controlled, and the intermediate C-3 enolate is trapped with a second Michael acceptor. The developed one-pot three-component consecutive reactions generate up to four contiguous stereocenters, including the C-3 all-carbon quaternary center, in a perfectly defined configuration. The conversion of the beta-nitro oxindole into the corresponding beta-amino derivative discloses synthetically useful transformations, exploitable to generate pharmaceutically attractive molecular targets.
Titolo: | Organocatalytic Conjugate Addition of Nitroalkanes to 3-Ylidene Oxindoles: A Stereocontrolled Diversity Oriented Route to Oxindole Derivatives |
Autore/i: | QUINTAVALLA, ARIANNA; Francesco Lanza; MONTRONI, ELISA; LOMBARDO, MARCO; TROMBINI, CLAUDIO |
Autore/i Unibo: | |
Anno: | 2013 |
Rivista: | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1021/jo402099p |
Abstract: | An efficient and highly enantioselective Michael addition of nitroalkanes to 3-ylidene oxindoles is described, mediated by thiourea-based bifunctional organocatalysts. The stereochemistry at C-alpha and C-beta centers is perfectly controlled, and the intermediate C-3 enolate is trapped with a second Michael acceptor. The developed one-pot three-component consecutive reactions generate up to four contiguous stereocenters, including the C-3 all-carbon quaternary center, in a perfectly defined configuration. The conversion of the beta-nitro oxindole into the corresponding beta-amino derivative discloses synthetically useful transformations, exploitable to generate pharmaceutically attractive molecular targets. |
Data prodotto definitivo in UGOV: | 2014-03-27 12:13:57 |
Appare nelle tipologie: | 1.01 Articolo in rivista |