Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

Brigita Mudráková; Renata Marcia de Figueiredo; Jean-Marc Campagne; Radovan Šebesta

doi:10.3762/bjoc.19.65

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

Beilstein J Org Chem. 2023 Jun 16:19:881-888. doi: 10.3762/bjoc.19.65. eCollection 2023.

Authors

Brigita Mudráková¹, Renata Marcia de Figueiredo², Jean-Marc Campagne², Radovan Šebesta¹

Affiliations

¹ Comenius University Bratislava, Faculty of Natural Sciences, Department of Organic Chemistry, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia.
² ICGM, University of Montpellier, CNRS, ENSCM, Montpellier, France.

Abstract

We present here a stereoselective tandem reaction based on the asymmetric conjugate addition of dialkylzinc reagents to unsaturated acylimidazoles followed by trapping of the intermediate zinc enolate with carbocations. The use of a chiral NHC ligand provides chiral zinc enolates in high enantiomeric purities. These enolates are reacted with highly electrophilic onium compounds to afford densely substituted acylimidazoles. DFT calculations helped to understand the reactivity of the zinc enolates derived from acylimidazoles and allowed their comparison with metal enolates obtained by other conjugate addition reactions.

Keywords: acylimidazole; asymmetric catalysis; carbocation; conjugate addition; enolate.

Grants and funding

This work was supported by the Slovak Research and Development Agency under the Contract no. APVV-18-0242 and by the Operation Program of Integrated Infrastructure for the project, UpScale of Comenius University Capacities and Competence in Research, Development and Innovation, ITMS2014+: 313021BUZ3, co-financed by the European Regional Development Fund.