title: Synthesis of Glycoborine, Glybomine A and B, the Phytoalexin Carbalexin A and the β-Adrenoreceptor Antagonists Carazolol and Carvedilol.
abstract: We describe a regioselective synthesis of 4- or 5-substituted carbazoles by oxidative cyclisation of meta-oxygen-substituted N-phenylanilines. Using the regiodirecting effect of a pivaloyloxy group, we prepared 4-hydroxycarbazole, a precursor for the enantiospecific synthesis of the β-adrenoreceptor antagonists (-)-(S)-carazolol (5) and (-)-(S)-carvedilol (6). Regioselective palladium(II)-catalysed cyclisation of different diarylamines led to total synthesis of glycoborine (7) and the first total syntheses of the phytoalexin carbalexin A (8), glybomine A (9) and glybomine B (10). For glybomine B (10), a 5-hydroxycarbazole was converted into the corresponding triflate and utilized for introduction of a prenyl substituent.
authors: Department Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
authors: Christian
authors: C
authors: Brütting
authors: Department Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
authors: Ronny
authors: R
authors: Hesse
authors: Department Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
authors: Anne
authors: A
authors: Jäger
authors: Department Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
authors: Olga
authors: O
authors: Kataeva
authors: Department Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
authors: Arndt W
authors: AW
authors: Schmidt
authors: Department Chemie, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
authors: Hans-Joachim
authors: HJ
authors: Knölker
mesh_terms: D002227:Carbazoles / Q000138:chemical synthesis*; D000077261:Carvedilol; D002384:Catalysis; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003500:Cyclization; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry; D011412:Propanolamines / Q000138:chemical synthesis; D012717:Sesquiterpenes / Q000138:chemical synthesis; D021241:Spectrometry, Mass, Electrospray Ionization; D000094162:Phytoalexins
chemical_list: D002227:Carbazoles; D011412:Propanolamines; D012717:Sesquiterpenes; C493074:glybomine A; C493076:glybomine B; D000077261:Carvedilol; C014382:carazolol; D010165:Palladium; D000094162:Phytoalexins
keywords: C−H bond activation; alkaloids; catalysis; natural products; palladium