title: Pyrrolidinyl-camphor derivatives as a new class of organocatalyst for direct asymmetric Michael addition of aldehydes and ketones to beta-nitroalkenes.
abstract: Practical and convenient synthetic routes have been developed for the synthesis of a new class of pyrrolidinyl-camphor derivatives (7 a-h). These novel compounds were screened as catalysts for the direct Michael addition of symmetrical alpha,alpha-disubstituted aldehydes to beta-nitroalkenes. When this asymmetric transformation was catalyzed by organocatalyst 7 f, the desired Michael adducts were obtained in high chemical yields, with high to excellent stereoselectivities (up to 98:2 diastereomeric ratio (d.r.) and 99 % enantiomeric excess (ee)). The scope of the catalytic system was expanded to encompass various aldehydes and ketones as the donor sources. The synthetic application was demonstrated by the synthesis of a tetrasubstituted-cyclohexane derivative from (S)-citronellal, with high stereoselectivity.
authors.affiliation: Department of Chemistry, National Taiwan Normal University, Taipei, 116, ROC, Taiwan.
authors.forename: Ying-Fang
authors.initials: YF
authors.lastname: Ting
authors.forename: Chihliang
authors.initials: C
authors.lastname: Chang
authors.forename: Raju Jannapu
authors.initials: RJ
authors.lastname: Reddy
authors.forename: Dhananjay R
authors.initials: DR
authors.lastname: Magar
authors.forename: Kwunmin
authors.initials: K
authors.lastname: Chen
mesh_terms: D000080462:Acyclic Monoterpenes; D000447:Aldehydes / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry*; D002164:Camphor / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003510:Cyclohexanes / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D039821:Monoterpenes / Q000737:chemistry*; D009574:Nitro Compounds / Q000737:chemistry*; D011759:Pyrrolidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000080462:Acyclic Monoterpenes; D000447:Aldehydes; D000475:Alkenes; D003510:Cyclohexanes; D007659:Ketones; D039821:Monoterpenes; D009574:Nitro Compounds; D011759:Pyrrolidines; D002164:Camphor; C108217:citronellal