title: Diastereo-Divergent Synthesis of Saturated Azaheterocycles Enabled by tBuOK-Mediated Hydroamination of Alkenyl Hydrazones.
abstract: Diastereo-divergent synthesis of saturated azaheterocycles has been achieved by tBuOK-mediated hydroamination of alkenyl hydrazones. DFT calculations suggested that the cation-π interactions between a potassium cation and aryl substituents on hydrazones give rise to 2,5-cis selectivity in pyrrolidines, which were synthesized by the reaction of γ,δ-unsaturated N-benzyl hydrazones. By contrast, 2,5-trans selectivity was observed when an isopropyl group was used as the substituent on hydrazones. An unusual 2,6-trans selectivity in piperidine formation was also realized using the present strategy.
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore).
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kaga
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore).
authors.forename: Xingao
authors.initials: X
authors.lastname: Peng
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore).
authors.forename: Hajime
authors.initials: H
authors.lastname: Hirao
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore). shunsuke@ntu.edu.sg.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Chiba
keywords: density functional calculations; hydrazones; hydroamination; piperidines; pyrrolidines