Another possible source of error is the use of r 2 SCAN-3c, which employs a relatively small basis set. We thus compared the r 2 SCAN-3c results to corresponding B3LYP/def2-TZVP and DLPNO-CCSD(T)/def2-TZVPP results (Figures and) for the first entry in Table , but all three methods lead to a prediction of β selectivity. So neither conformational sampling or QM level of theory can explain the few discrepancies with experiment observed for this dataset.