Enantioselective Catalytic Conjugate Addition of Dialkylzinc Reagents using Copper–Phosphoramidite Complexes; Ligand Variation and Non-linear Effects

✍ Scribed by Leggy A Arnold; Rosalinde Imbos; Alessandro Mandoli; André H.M de Vries; Robert Naasz; Ben L Feringa

• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 315 KB
• Volume: 56
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(00)00142-3

✦ Synopsis

AbstractÐA variety of new chiral phosphoramidites was synthesised and tested in the copper-catalysed enantioselective conjugate addition of diethylzinc to cyclohexenone and chalcone in order to assess the structural features that are important for stereocontrol. A sterically demanding amine moiety is essential to reach high e.e.'s. Enantioselectivities for chalcones up to 89% and for cyclic enones up to 98% were found. Studies on non-linear effects with the best ligands for both cyclohexenone and chalcone showed clear non-linear effects for both cyclic and acyclic enones.