Can photocatalysis be performed without electron or energy transfer? To address this, organo-photocatalysts that are based on atropisomeric thioureas and display lower excited-state energies than the reactive substrates have been developed. These photocatalysts were found to be efficient in promoting the [2+2] photocycloaddition of 4-alkenyl-substituted coumarins, which led to the corresponding products with high enantioselectivity (77-96% ee) at low catalyst loading (1-10 mol%). The photocatalytic cycle proceeds by energy sharing via the formation of both static and dynamic complexes (exciplex formation), which is aided by hydrogen bonding.

Nonisocyanate polyurethane (NIPU) thermoset networks were produced from a novel soybean-oil-derived poly­(vinyl ether) (i.e., poly­[(2-vinyoxy)­ethyl soyate]) possessing cyclic carbonate functional groups in the fatty acid ester side chains of the polymer. Three different linear aliphatic diamines, namely, 1,6-hexamethylenediamine, 1,9-nonanediamine, and 1,13-tridecanediamine, were used to cross-link the cyclic carbonate-functional poly­[(2-vinyoxy)­ethyl soyate] [C-poly­(2-VOES)]. All three of these diamines can be readily obtained from renewable resources. For comparison purposes, analogous NIPU networks were produced using cyclic carbonate-functional soybean oil (CSBO) in place of the C-poly­(2-VOES). The chemical, thermal, viscoelastic, and mechanical properties of the six NIPU networks were characterized. With regard to the chemical nature of the soy-based, carbonate-functional component, it was found that the polymeric nature of C-poly­(2-VOES) resulted in very different NIPU properties compared to analogous cross-linked networks based on CSBO. While the CSBO-based NIPU networks exhibited lower Young’s moduli and ductile behavior, the networks based on C-poly­(2-VOES) showed significantly higher Young’s moduli and brittle behavior. In addition, measurements using dynamic mechanical analysis showed significantly high cross-link densities for the networks based on C-poly­(2-VOES), which can be attributed to a much higher number of methine carbon atoms per molecule in C-poly­(2-VOES) as compared to CSBO. In addition to the cross-links resulting from the reaction of the amine groups of the cross-linker with the cyclic carbonate groups of the soy-based carbonate-functional materials, these methine carbon atoms serve as cross-links in the NIPU networks. The higher cross-link densities achieved with the use of C-poly­(2-VOES) explain the thermal and mechanical property differences observed between networks based on the two different soy-based carbonate-functional materials. With regard to the influence of the diamines on NIPU network properties, as expected, increasing the chain length of the diamine cross-linker decreased cross-link density, which, in general, resulted in decreases in Young’s moduli and glass transition temperature.

Direct acyl radical formation of linear aldehydes (RCH2-CHO) and subsequent hydroacylation with electron-deficient olefins can be effected with various types of metal and nonmetal catalysts/reagents. In marked contrast, however, no successful reports on the use of branched aldehydes have been made thus far because of their strong tendency of generating alkyl radicals through the facile decarbonylation of acyl radicals. Here, use of a hypervalent iodine(III) catalyst under visible light photolysis allows a mild way of generating acyl radicals from various branched aldehydes, thereby giving the corresponding hydroacylated products almost exclusively. Another characteristic feature of this approach is the catalytic use of hypervalent iodine(III) reagent, which is a rare example on the generation of radicals in hypervalent iodine chemistry.

A new 100% bio-based thermosetting coating system was developed from epoxidized sucrose soyate crosslinked with blocked bio-based dicarboxylic acids. A solvent-free, green method was used to block the carboxylic acid groups and render the acids miscible with the epoxy resin. The thermal reversibility of this blocking allowed for the formulation of epoxy-acid thermoset coatings that are 100% bio-based. This was possible due to the volatility of the vinyl ethers under curing conditions. These systems have good adhesion to metal substrates and perform well under chemical and physical stress. Additionally, the hardness of the coating system is dependent on the chain length of the diacid used, making it tunable.

Biomass-derived 2,5-furandicarboxylic acid was valorized by conversion to 1,4-naphthalenedicarboxylic acid via benzyne-cycloaddition and reductive aromatization in 66% overall yield (four steps).