Fig. 1. Mechanistic investigations. (a) Standard reaction conditions with benzoic acid 1A at 50 °C for 30 min. (b) Energies calculated in acetonitrile (B3LYP-D3BJ/6-31+G(d)).24 Gibbs free energies (G) in kcal mol–1. (c) Experimental KIEs (in black), the uncertainty on the last figure is reported in brackets. For C4 a KIE of 1.000 was assumed.25 Calculated KIEs (in red) for the proposed path.26.
