title: A highly efficient organocatalyst for direct aldol reactions of ketones with aldehydes [corrected].
abstract: L-proline amides derived from various chiral beta-amino alcohols that bear substituents with various electron natures at their stereogenic centers are prepared and evaluated for catalyzing the direct Aldol reaction of 4-nitrobenzaldehyde with acetone. Catalysts with strong electron-withdrawing groups are found to exhibit higher catalytic activity and enantioselectivity than their analogues with electron-donating groups. The presence of 2 mol % catalyst 4g significantly catalyzes the direct Aldol reactions of a wide range of aldehydes with acetone and butanone, to give the beta-hydroxy ketones with very high enantioselectivities ranging from 96% to >99% ee. High diastereoselectivity of 95/5 was observed for the anti Aldol product from the reaction of cyclohexanone, and excellent enantioselectivity of 93% ee was provided for anti Aldol product from the reaction of cyclopentanone.
authors.affiliation: Key Laboratory for Asymmetric Synthesis and Chirotechnology of Sichuan Province, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, China.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Tang
authors.forename: Zhi-Hua
authors.initials: ZH
authors.lastname: Yang
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Chen
authors.forename: Lin-Feng
authors.initials: LF
authors.lastname: Cun
authors.forename: Ai-Qiao
authors.initials: AQ
authors.lastname: Mi
authors.forename: Yao-Zhong
authors.initials: YZ
authors.lastname: Jiang
authors.forename: Liu-Zhu
authors.initials: LZ
authors.lastname: Gong
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis* / Q000737:chemistry; D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D011392:Proline / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D000577:Amides; D007659:Ketones; D011392:Proline