DFT calculations induced a regiochemical outcome revision of the Diels–Alder reaction between levoglucosenone and isoprene

An appealing inversion in the regiochemical outcome of Diels–Alder reactions between levoglucosenone (1) and its α-bromo derivative (5) with isoprene (2) was studied computationally. Based on different DFT calculations we concluded that both reactions should display the same regioselectivity. This result was further validated experimentally.