Salalen vs. thiolen: in the ring(-opening of epoxide and cyclic carbonate formation)

A range of Fe(III)-salalen and -thiolen–chloride complexes have been prepared and are shown to be active catalysts for the selective coupling of CO2 and cyclohexene oxide (CHO). The first Fe(III)-thiolen–acetate complex is also reported. The effect of the structure of the complex on activity is explored. An epoxide substrate scope is also provided, using the most active catalyst, as well as a study into the effect of co-catalyst equivalents on activity and selectivity.