Unprecedented Diastereoselective Arylogous Michael Addition of Unactivated Phthalides |
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| Authors: | Marina Sicignano Dr. Rosaria Schettini Luisa Sica Giovanni Pierri Prof. Dr. Francesco De Riccardis Prof. Dr. Irene Izzo Dr. Bholanath Maity Dr. Yury Minenkov Prof. Dr. Luigi Cavallo Dr. Giorgio Della Sala |
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| Affiliation: | 1. Dipartimento di Chimica e Biologia “Adolfo Zambelli”, Università degli Studi di Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy;2. KAUST Catalysis Center, KCC, King Abdullah University of Science and Technology, KAUST, Thuwal, 23955-6900 Saudi Arabia), E-mail;3. Moscow Institute of Physics and Technology, MIPT, Institutskiy Pereulok 9, 141700 Dolgoprudny, Moscow Region, Russia |
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| Abstract: | The first highly enantioselective arylogous Michael reaction (AMR) of 3-unsubstituted phthalides has been described. This phase-transfer methodology, which uses catalytic amounts of KOH/18-crown-6 catalyst in mesitylene in the presence of N,O-bis(trimethylsilyl)acetamide (BSA), gives access to a broad range of 3-monosubstituted phthalides with high levels of syn diastereoselectivity and good yields, starting from 3-unsubstituted derivatives and diverse α,β-unsaturated carbonyl compounds. The reaction also applies to unactivated 3-alkyl phthalides to afford 3,3-dialkyl derivatives. A plausible mechanism has been suggested. DFT analysis of possible transition states gives a rationale of the high syn diastereoselectivity observed and its correlation with the solvent's dielectric constant. |
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| Keywords: | crown compounds density functional calculations diastereoselectivity Michael addition phthalides |
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