title: Silicon-based Lewis acid assisted cinchona alkaloid catalysis: highly enantioselective aza-Michael reaction under solvent-free conditions.
abstract: The study showed that a combination of an achiral silicon-based Lewis acid and chiral Lewis base, such as iodotrimethylsilane (TMSI) and cinchonine, generated a highly enantioselective catalyst system under solvent-free conditions which gave aromatic β-amino ketones with up to >99% ee. Mechanistic studies demonstrate the enhanced asymmetric induction may be due to the combined and competitive activation of a carbonyl moiety of chalcone with cinchonine and the silicon-based Lewis acid in the aza-Michael reaction.
authors.affiliation: Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou 310012, P. R. China.
authors.forename: Hua-Meng
authors.initials: HM
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Li
authors.forename: Ke-Zhi
authors.initials: KZ
authors.lastname: Jiang
authors.forename: Jun-Yan
authors.initials: JY
authors.lastname: Shang
authors.forename: Guo-Qiao
authors.initials: GQ
authors.lastname: Lai
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Xu
mesh_terms: D002384:Catalysis; D047188:Chalcones / Q000737:chemistry*; D002930:Cinchona Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000138:chemical synthesis / Q000737:chemistry; D058116:Lewis Acids / Q000737:chemistry; D015394:Molecular Structure; D012821:Silanes / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D047188:Chalcones; D002930:Cinchona Alkaloids; D007659:Ketones; D058116:Lewis Acids; D012821:Silanes