title: Catalytic asymmetric amination of N-nonsubstituted α-alkoxycarbonyl amides: concise enantioselective synthesis of mycestericin F and G.
abstract: In an attempt to explore the synthetic utility of a ternary asymmetric catalyst comprising La(NO(3))(3)·6H(2)O, amide-based ligand (R)-L1, and D-valine tert-butyl ester H-D-Val-OtBu, we investigated a catalytic, asymmetric amination of functionalized N-nonsubstituted α-alkoxycarbonyl amides using di-tert-butyl azodicarboxylate as an electrophilic aminating reagent. A highly functionalized, cyclic N-nonsubstituted α-alkoxycarbonyl amide delivered the desired amination product in up to 96% enantiometric excess, with the requisite functionalities of the polar heads of sphingosines with the appropriate stereochemical arrangement. The rapid asymmetric assembly of these functional groups allowed a concise enantioselective synthetic route to sphingosines to be established with a broad flexibility towards derivative synthesis. These studies have culminated in an efficient catalytic enantioselective total synthesis of immunosuppressive fungal metabolites mycestericin F (3a) and G (3b).
authors.affiliation: Institute of Microbial Chemistry, Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan.
authors.forename: Farouk
authors.initials: F
authors.lastname: Berhal
authors.forename: Sho
authors.initials: S
authors.lastname: Takechi
authors.forename: Naoya
authors.initials: N
authors.lastname: Kumagai
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Shibasaki
mesh_terms: D000577:Amides / Q000737:chemistry*; D000586:Amination; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D002384:Catalysis; D005231:Fatty Acids, Unsaturated / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000577:Amides; D001688:Biological Products; D005231:Fatty Acids, Unsaturated; D007166:Immunosuppressive Agents; C102387:mycestericin F