title: Bifunctional-thiourea-catalyzed diastereo- and enantioselective aza-Henry reaction.
abstract: Bifunctional thiourea 1a catalyzes aza-Henry reaction of nitroalkanes with N-Boc-imines to give syn-beta-nitroamines with good to high diastereo- and enantioselectivity. Apart from the catalyst, the reaction requires no additional reagents such as a Lewis acid or a Lewis base. The N-protecting groups of the imines have a determining effect on the chirality of the products, that is, the reaction of N-Boc-imines gives R adducts as major products, whereas the same reaction of N-phosphonoylimines furnishes the corresponding S adducts. Various types of nitroalkanes bearing aryl, alcohol, ether, and ester groups can be used as nucleophiles, providing access to a wide range of useful chiral building blocks in good yield and high enantiomeric excess. Synthetic versatility of the addition products is demonstrated by the transformation to chiral piperidine derivatives such as CP-99,994.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Xuenong
authors.initials: X
authors.lastname: Xu
authors.forename: Tomihiro
authors.initials: T
authors.lastname: Furukawa
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Okino
authors.forename: Hideto
authors.initials: H
authors.lastname: Miyabe
authors.forename: Yoshiji
authors.initials: Y
authors.lastname: Takemoto
mesh_terms: D002384:Catalysis; D003959:Diamines / Q000138:chemical synthesis; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D009574:Nitro Compounds / Q000737:chemistry*; D009595:Nitroparaffins / Q000737:chemistry; D010880:Piperidines / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013890:Thiourea / Q000737:chemistry*
chemical_list: D003959:Diamines; D009574:Nitro Compounds; D009595:Nitroparaffins; D010880:Piperidines; D013890:Thiourea; D008697:Methane; C008640:nitromethane