title: TiCl4-promoted cyclization reactions of aminoacetals and ethenetricarboxylates leading to nitrogen-containing heterocycles.
abstract: Lewis acid-catalyzed cyclization of aminoacetals 2 and triethyl ethenetricarboxylate (1a) has been examined. The reaction of 3-aminopropionaldehyde diethyl acetal (2a) and 1a in the presence of 1 equiv of TiCl(4) at room temperature gave 4-ethoxypiperidine-2,3,3-tricarboxylate 3a in 92% yield with a 2,4-diastereomer ratio of 1:1. The reaction in the presence of 3 equiv of TiCl(4) gave 2,4-trans-piperidine derivative 3a in 86% yield predominantly. The reaction of aminoacetaldehyde diethyl/dimethyl acetals 2c,d and 1a with 3 equiv of TiCl(4) gave 2,4-trans-4-pyrrolidine-2,3,3-tricarboxylates 5a,b predominantly.
authors.affiliation: Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan. yamazaks@nara-edu.ac.jp
authors.forename: Shoko
authors.initials: S
authors.lastname: Yamazaki
authors.forename: Masachika
authors.initials: M
authors.lastname: Takebayashi
mesh_terms: D000080:Acetals / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000737:chemistry*; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*; D013237:Stereoisomerism; D014025:Titanium / Q000737:chemistry*; D014233:Tricarboxylic Acids / Q000737:chemistry*
chemical_list: D000080:Acetals; D006571:Heterocyclic Compounds; D014233:Tricarboxylic Acids; C025096:titanium tetrachloride; D014025:Titanium; D009584:Nitrogen