Renewable Beta-Elemene Based Cyclic Carbonates for the Preparation of Oligo(hydroxyurethane)s.

Conversion of β-elemene into new β-elemene dicarbonates through epoxidation and halide salt-catalyzed CO cycloaddition reactions is reported. Step-growth polyaddition of this dicarbonate to five different, commercial diamines was investigated under neat conditions at 150 °C yielding non-isocyanate-based low molecular weight oligo(hydroxyurethane)s with 1.3≤M ≤6.

Organocatalyzed Domino [3+2] Cycloaddition/Payne-Type Rearrangement using Carbon Dioxide and Epoxy Alcohols.

An unprecedented organocatalytic approach towards highly substituted cyclic carbonates from tri- and tetrasubstituted oxiranes and carbon dioxide has been developed. The protocol involves the use of a simple and cheap superbase under mild, additive- and metal-free conditions towards the initial formation of a less substituted carbonate product that equilibrates to a tri- or even tetrasubstituted cyclic carbonate under thermodynamic control. The latter are conveniently trapped in situ, providing overall a new domino process for synthetically elusive heterocyclic scaffolds.