title: Catalytic asymmetric three-component 1,3-dipolar cycloaddition of aldehydes, hydrazides, and alkynes.
abstract: Catalytic asymmetric 1,3-dipolar cycloadditions offer expeditious ways to afford synthetically important chiral heterocycles. Although a variety of 1,3-dipoles can be employed in this context, the use of acyclic azomethine imines as a facile means to give chiral pyrazolines and pyrazolidines remains completely unexplored. We report herein the first catalytic asymmetric 1,3-dipolar cycloaddition of terminal alkynes with acyclic azomethine imines generated in situ from the corresponding aldehydes and hydrazides, which was realized using Cu(I)/pybox and axially chiral dicarboxylic acid cocatalysts.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Yuka
authors.initials: Y
authors.lastname: Takiguchi
authors.forename: Keiji
authors.initials: K
authors.lastname: Maruoka