Enantioselective Small Molecule Synthesis by Carbon Dioxide Fixation using a Dual Brønsted Acid/Base Organocatalyst

Carbon
dioxide exhibits many of the qualities of an ideal reagent: it is
nontoxic, plentiful, and inexpensive. Unlike other gaseous reagents,
however, it has found limited use in enantioselective synthesis. Moreover,
unprecedented is a tool that merges one of the simplest biological
approaches to catalysisBrønsted acid/base activationwith
this abundant reagent. We describe a metal-free small molecule catalyst
that achieves the three component reaction between a homoallylic alcohol,
carbon dioxide, and an electrophilic source of iodine. Cyclic carbonates
are formed enantioselectively.