Iridium-Catalyzed Asymmetric Ring-Opening of Oxabenzonorbornadienes with N-Substituted Piperazine Nucleophiles

Wen Yang; Renshi Luo; Dingqiao Yang

doi:10.3390/molecules201219748

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabenzonorbornadienes with N-Substituted Piperazine Nucleophiles

Molecules. 2015 Nov 27;20(12):21103-24. doi: 10.3390/molecules201219748.

Authors

Wen Yang¹, Renshi Luo², Dingqiao Yang³

Affiliations

¹ Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China. 18971194938@yeah.net.
² School of Pharmaceutical Sciences, Gannan Medical University, Yi Xue Yuan Road, Ganzhou 341000, China. luorenshi2010@163.com.
³ Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China. yangdq@scnu.edu.cn.

Abstract

Iridium-catalyzed asymmetric ring-opening of oxabenzonorbornadienes with N-substituted piperazines was described. The reaction afforded the corresponding ring-opening products in high yields and moderate enantioselectivities in the presence of 2.5 mol % [Ir(COD)Cl]₂ and 5.0 mol % (S)-p-Tol-BINAP. The effects of various chiral bidentate ligands, catalyst loading, solvent, and temperature on the yield and enantioselectivity were also investigated. A plausible mechanism was proposed to account for the formation of the corresponding trans-ring opened products based on the X-ray structure of product 2i.

Keywords: N-substituted piperazines; asymmetric ring-opening; chiral bisphosphine ligand; iridium catalyst; oxabenzonorbornadiene.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Boronic Acids / chemistry*
Catalysis
Crystallography, X-Ray
Iridium / chemistry*
Molecular Structure
Norbornanes / chemistry*
Piperazine
Piperazines / chemistry*
Stereoisomerism

Substances

Boronic Acids
Norbornanes
Piperazines
Piperazine
Iridium