Thermal Rearrangement Reactions of Polyynes and Preparation of Bio-renewable Monomers and Their Polymerizations

Abstract

Part I: This study explored several novel features of the hexadehydro-Diels-Alder (HDDA) reaction of substrates containing tethered trapping moieties. Three aspects are estiblished experimentally: i) Medium-sized fused rings can be produced by varying the length of the tether; ii) The tether can emanate (see red arc) from an atom within the linker unit that joins the 1,3-diyne and the diynophile; iii) The importance of the rate of trapping by the benzynophile is established. Part II: An unprecedented rearrangement reaction of alkynyl ynedione substrate is discovered, and the product of this process is butenolide-type compounds. The mechanism of this process has been thoroughly studied by both experimental and computational methods. Part III: The first conversion of α-methyleneglutaric anhydride to (a series of) α- methyleneglutarimides has been realized. These potentially bio-renewable monomers can then be polymerized to the corresponding polymers. These polymeric materials showed promising physical properties, including relatively high glass transition temperatures. The depolymerization process was also studied. Part IV: A ketolactone monomer has been made from bio-sourced levulinic acid via a simple and scalable process. The polymerization reaction of this monomer gives a novel class of polyester and the polyester showed a series of promising properties.