Polymerization-like mechanism for fixation of CO 2 with epoxides by multifunctional organocatalysts.

The commonly accepted mechanism of CO 2 fixation of epoxides to cyclic carbonates catalyzed by multifunctional non-halide organocatalysts is challenged by our computational DFT-D3 study, which revealed a new polymerization-like mechanism comprising alternate epoxide and CO 2 activation steps and a nested CO 2 activation pathway. We investigated a recently reported CO 2 coupling with epoxide reaction catalyzed by a bis-phenolic multifunctional catalyst. The predicted cis / trans product ratio is in excellent agreement with experimental results. The general applicability of the new mechanism is supported by another diamine-diacid catalyzed CO 2 fixation reaction.