This data set includes output files from the quantum chemical calculations run with Gaussian16 (Revision C.01) that support our computational mechanistic study of the enantioselective [1,2]-Wittig rearrangement of allylic ethers. It also contains three sets of in situ reaction monitoring data (collected by University of St Andrews contributors) and a Python script that fits the rate constants of a first-order kinetics model to the experimental data.