Chiral Cu(II)‐N4 Complex Catalyzed Asymmetric Aza‐Henry Reaction and Its Application in the Synthesis of β‐Diamine. Issue 14 (19th May 2017)

• Record Type: Journal Article
• Authors: Menapara, Tusharkumar; Tak, Rajkumar; Chinnaraja, E.; Kureshy, Rukhsana I.; Patel, Parth; Khan, Noor‐ul H.
• Is Part Of: ChemistrySelect. Volume 2:Issue 14(2017)
• Page Start: 4063
• Page End: 4067
• Publication Date: 2017-05-19
• Subjects: Aza-Henry reaction -- β-diamines -- isatin derived N-Boc ketimines -- nitroalkanes; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201700551
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: ChiralCu(II)‐L3 complex was generated In situ to catalyze the asymmetric aza‐Henry reaction of various isatin derived N ‐Boc ketimines with nitromethane, nitroethane and 1‐nitropropane as nucleophiles at room temperature. High yield (up to 84 %) and excellent chiral induction (ee, up to 99 %) of β ‐nitroamine was obtained in 13 h. The β ‐nitroamine(1 g) was conveniently hydrogenated to enantiomerically pure ( S )‐ β ‐diamine in good yield and high enantioselectivity. The kinetic investigation was undertaken to understand the reaction mechanism of the catalytic aza‐Henry reaction usingCu(II)‐L3 as catalyst, with nitromethane and isatin N ‐Boc ketimine(1 g) as a representative substrate. Abstract : Cu(II)‐N4 catalyzed enantioselective aza‐Henry reaction of isatine derived N ‐Boc ketimine was reported in this study. Catalyst Cu(II)‐L3 afforded excellent enantioselectivity (up to 99 %) and good yield (up to 84 %) with nitromethane. Moderate yield (up to 75 %) and diastereoselectivity (up to 93:07) with excellent enantioselectivity (up to 95 %) was achieved in corresponding products with nitroethane and 1‐nitropropane. β ‐nitroamine is successfully reduced to the corresponding β ‐diamine. A probable mechanism based on kinetic study is proposed.