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Macrocyclic Polyethers as Enolate Activators in Homogeneous and Heterogeneous Systems |
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| Authors: | Angelamaria Maia Dario Landini Silvia Petricci |
| Affiliation: | Centro CNR and Dipartimento di Chimica Organica e Industriale dell' Università , Via Golgi 19, 1-20133, Milano, Italy |
| Abstract: | Abstract The ability of macrocyclic polyethers to activate enolates has been studied in the alkylation of deoxybenzoin (1) with butyl derivatives nBuY (Y = Br, I, OMes) catalyzed by crown ether PHDB18C6 (7) or cryptand [2.2.2, C10] (8) under phase-transfer catalysis (PTC) and homogeneous (chlorobenzene) conditions. The enolate reactivity is mainly determined by the ligand (cryptand>crown ether) and solvent (increasing with the polarity, in the order: toluene |
| Keywords: | Activation of enolates lipophilic macrocyclic polyethers phase-transfer catalysis (PTC) regioselectivity in alkylation reactions solvent effects in PTC reactions UV-vis determinations of enolates |