title: Copper-mediated oxidative transformation of N-allyl enamine carboxylates toward synthesis of azaheterocycles.
abstract: A method for synthesis of 3-azabicyclo[3.1.0]hex-2-enes has been developed by intramolecular cyclopropanation of readily available N-allyl enamine carboxylates. Two complementary reaction conditions, CuBr-mediated aerobic and CuBr2-catalyzed-PhIO2-mediated systems effectively induced stepwise cyclopropanation via carbocupration of alkenes. Oxidative cyclopropane ring-opening of 5-substituted 3-azabicyclo[3.1.0]hex-2-enes was also developed for synthesis of highly substituted pyridines. In addition, diastereoselective reduction of 3-azabicyclo[3.1.0]hex-2-enes to 3-azabicyclo[3.1.0]hexanes was achieved using NaBH3CN in the presence of acetic acid.
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Kah Kah
authors.initials: KK
authors.lastname: Toh
authors.forename: Anup
authors.initials: A
authors.lastname: Biswas
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Wang
authors.forename: Yun Yun
authors.initials: YY
authors.lastname: Tan
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Chiba
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic; D003300:Copper / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000475:Alkenes; D000588:Amines; D002264:Carboxylic Acids; D006571:Heterocyclic Compounds; D011725:Pyridines; D003300:Copper; C023666:pyridine