Tin(IV)-Porphyrin Tetracarbonyl Cobaltate: An Efficient Catalyst for the Carbonylation of Epoxides

Ek Raj Baral,Sunwoo Lee,Dongwook Kim,Jeung Gon Kim,Myung Hwan Park

doi:10.3390/catal9040311

Abstract

Cationic tin(IV) porphyrins with tetracarbonyl cobaltates were synthesized, exhibiting bifunctional catalytic reactivity. The Lewis acidic tin-porphyrin center activated epoxides; concurrently, cobalt carbonyl anions efficiently opened epoxides and delivered carbonyl moieties. Thus, a series of β-lactones with a high synthetic value were obtained. This catalytic system showed excellent efficiency exceeding a turnover number of one thousand with a broad substrate scope. In addition, the presented tin porphyrin-based catalyst exhibited exclusive chemoselectivity to terminal epoxides over internal ones. The selective carbonylation of di-epoxides demonstrated the usefulness of these catalysts in the synthesis of complex molecular structures.

Highlights

Porphyrins and metalloporphyrins are found in many living organisms and play an essential role in sustaining life [1,2,3,4]
Many natural and nonnatural porphyrins and their derivatives have been widely used in versatile applications such as medicine, materials, catalysis, supramolecular chemistry, and biomimetic models [15,16,17,18,19,20,21]
The cationic porphyrin units with a +2 charge are balanced with non- or weakly coordinating anions such as ClO4 −, BF4 −, TfO−, Br−, F−, Cl−, and OH−

Summary

Introduction

Porphyrins and metalloporphyrins are found in many living organisms and play an essential role in sustaining life [1,2,3,4]. In the area of catalysis, numerous porphyrins, especially transition metal-based metalloporphyrins, promote many chemical transformations with high efficiency and reactivity; catalytic evaluation of main-group metal and semi-metal porphyrins has not received much attention despite the distinctive physical and chemical properties of such porphyrins [22,23,24,25,26]. Among those complexes, tin(IV) porphyrins have attracted our attention. The cationic porphyrin units with a +2 charge are balanced with non- or weakly coordinating anions such as ClO4 − , BF4 − , TfO− , Br− , F− , Cl− , and OH−

Methods

Results

Conclusion