Asymmetric Michael Addition of Cyclohexanone or Cyclopentanone to Chalcones Catalyzed by an L-Proline-Based Organic Phosphane

• Published in: European journal of organic chemistry Vol. 2013; no. 13; pp. 2634 - 2645
• Main Authors: Liu, Lingyan, Zhu, Yunna, Huang, Kaimeng, Chang, Weixing, Li, Jing
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.05.2013; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc
• Subjects: Asymmetric catalysis; Chemistry; Chemistry, Organic; Michael addition; Phosphanes; Physical Sciences; Science & Technology; Michael addition; CYCLIC-KETONES; ORGANOCATALYSTS; Phosphanes; ALDEHYDES; DIRECT ALDOL REACTION; ENANTIOSELECTIVE ADDITION; Asymmetric catalysis
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201201609

An organophosphane catalyst derived from L‐proline was shown to be a very effective catalyst for asymmetric Michael addition reactions of various chalcones to cyclic ketones including both cyclohexanone and cyclopentanone. The corresponding adducts could be obtained in high yields (up to 91 %) and with excellent enantioselectivities (up to 99 % ee) and diastereomeric ratios (up to >99:1). A possible catalytic mechanism, based on 31P NMR and ESI‐MS observations, for this organophosphane‐catalyzed Michael addition has been proposed. A simple organophosphane catalyst derived from L‐proline was shown to be a very effective catalyst for the asymmetric Michael addition of chalcones to cyclohexanone and to the weakly reactive cyclopentanone. The corresponding adducts could be obtained in high yields (up to 91 %) and with excellent enantioselectivities (up to 99 % ee) and diastereomeric ratios (up to >99:1).