Catalytic amidation of natural and synthetic polyol esters with sulfonamides

Hua Liu,Yi-Ling Zhu,Zhi Li

doi:10.1038/s41467-019-11864-9

Abstract

Triacylglycerides are naturally abundant and renewable feedstock for biofuels and chemicals. In this report, these seemingly stable compounds are shown to be reactive toward a variety of sulfonamides under Lewis acid catalysis. In these reactions, alkyl C(sp3)–O bonds are cleaved and C–N bonds constructed, providing functionalized value-added products directly from renewables. Mechanistic and scope study demonstrate that the origin of the reactivity could be the synergy of Lewis acid catalysis and neighboring group participation by the 2- or 3-acyloxy or acylamido group with respect to the reactive site. Since poly(ethylene terephthalate) (PET), a widely available consumer polyester, also contains 1,2-diol diester group as the repeating unit in the main chain, this chemistry can also be applied to efficient depolymerization of PET.

Highlights

Triacylglycerides are naturally abundant and renewable feedstock for biofuels and chemicals
Note that the glycol diacetate was added in an excess (2 equiv.) to facilitate better conversion of the sulfonamide nucleophile
Intrigued by the improved performance of saccharin, we investigated the reactivity between saccharin and tributyrin, a representative TAG

Summary

Introduction

Triacylglycerides are naturally abundant and renewable feedstock for biofuels and chemicals In this report, these seemingly stable compounds are shown to be reactive toward a variety of sulfonamides under Lewis acid catalysis. These seemingly stable compounds are shown to be reactive toward a variety of sulfonamides under Lewis acid catalysis In these reactions, alkyl C(sp3)–O bonds are cleaved and C–N bonds constructed, providing functionalized value-added products directly from renewables. One such effort destroys the glyceryl motif before release: direct decarboxylative cracking and hydrotreatment of TAGs to hydrocarbons using heterogeneous catalysts affords products that can be used directly as diesel fuels[14,15,16,17,18,19] These processes were typically performed at high temperatures (250–500 °C) and the C3 glyceryl motif was completely converted into propane which was too diluted to receive reasonable attention. These procedures can surely be applied to a general scope of esters, but for glycol diesters or TAGs it would be difficult to selectively convert one acyloxy group while keeping the other ones unchanged

Methods

Results

Conclusion