Here we report the bimolecular reaction of trifluoromethylhydroxycarbene conformers and the water-mediated mechanism of the 1,2-proton shift for the unimolecular trans-conformer by using quantum chemical calculations. The CCSD(T)/cc-pVTZ//MP2/cc-pVDZ potential-energy profile of the bimolecular reaction of cis- and trans-trifluoromethylhydroxycarbene, shows the lowest gas-phase barrier height of 13 kJ mol(-1) compared to the recently reported value of 128 kJ mol(-1) for the unimolecular reaction. We expect bimolecular reactions of carbene's stereoisomers will open a valuable field for new and useful synthetic strategies. (C) 2018 Elsevier B.V. All rights reserved.