title: Concise enantiospecific, stereoselective syntheses of (+)-crispine A and its (-)-antipode.
abstract: An enantiospecific and stereoselective total synthesis of the natural product (+)-crispine A has been demonstrated employing a Pictet-Spengler bis-cyclization reaction between commercially available (R)-(-)-methyl 2-amino-3-(3,4-dimethoxyphenyl)propanoate and 4-chloro-1,1-dimethoxybutane to preferentially provide the cis tricyclic adduct. Decarboxylation by a convenient two-step protocol provided the enantiopure natural product in three steps with an overall isolated yield of 32% from the amino acid. The unnatural antipode (-)-crispine A was similarly prepared in three steps from the commercially available (S)-(+)-amino acid.
authors.affiliation: Medicinal Chemistry Department, Albany Molecular Research, Inc. (AMRI), P.O. Box 15098, 26 Corporate Circle, Albany, New York 12212-5098, USA.
authors.forename: Mahender
authors.initials: M
authors.lastname: Gurram
authors.forename: Balázs
authors.initials: B
authors.lastname: Gyimóthy
authors.forename: Ruifang
authors.initials: R
authors.lastname: Wang
authors.forename: Sang Q
authors.initials: SQ
authors.lastname: Lam
authors.forename: Feryan
authors.initials: F
authors.lastname: Ahmed
authors.forename: R Jason
authors.initials: RJ
authors.lastname: Herr
mesh_terms: D001688:Biological Products / Q000138:chemical synthesis / Q000737:chemistry; D007546:Isoquinolines / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D014443:Tyrosine / Q000737:chemistry
chemical_list: D001688:Biological Products; D007546:Isoquinolines; C523713:crispine A; D014443:Tyrosine