Primary amines as heterogeneous catalysts in an enantioselective [2,3]-Wittig rearrangement reaction

Aleksandra Murre; Valdek Mikli; Kristin Erkman; Tõnis Kanger

doi:10.1016/j.isci.2023.107822

Primary amines as heterogeneous catalysts in an enantioselective [2,3]-Wittig rearrangement reaction

iScience. 2023 Sep 6;26(10):107822. doi: 10.1016/j.isci.2023.107822. eCollection 2023 Oct 20.

Authors

Aleksandra Murre¹, Valdek Mikli², Kristin Erkman¹, Tõnis Kanger¹

Affiliations

¹ Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
² Department of Materials and Environmental Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia.

Abstract

A series of heterogeneous catalysts anchored to different polystyrene-based supports has been prepared and applied in an asymmetric [2,3]-Wittig rearrangement reaction of cyclohexanone derivatives. Among them, primary amino acid-derived (aminomethylated)polystyrene-supported catalysts showed excellent reactivity leading to the formation of rearranged products in good enantioselectivities of both diastereomers. Reusability issues connected to the deactivation of the catalyst were proved to be dependent on the end-capping strategy chosen for the blocking of the unreacted active sites of the resin. This issue of end-capping has not previously been in focus. Using bulkier pivaloyl end-capping moiety, we were able to recycle the catalyst in six consecutive cycles with only marginal deceleration of the reaction. Moreover, the epimerization of the product that occurred while conducting a rearrangement reaction in the presence of a homogeneous catalyst was almost fully eliminated by switching the catalytic system to heterogeneous.

Keywords: Organic chemistry.