A Bottom-Up Synthetic Approach to Polyethylene Furanoate Model Compounds

The growing importance of polyethylene furanoate (PEF) as a potential biobased substitute for PET is sparking interest in developing strategies for the chemical recycling of PEF. Access to appropriate model compounds is desirable for the development of depolymerization methods as well as for studying molecular properties and reactivity of PEF models. Herein, we describe a bottom-up strategy for the efficient and selective preparation of specific chain fragments from 2,5-furandicarboxylic acid (FDCA) and monoethylene glycol (MEG). Since conventional esterification methods according to Fischer and Steglich proved to be ineffective for certain target compounds, a sequence that consists of one-sided FDCA protection, Mukaiyama esterification, and subsequent deprotection was developed. The strategy was successfully applied to the preparation of various model compounds, including examples that have not yet been described in the literature.