. Thus, the torsional strain energy of4ais calculated as below: $$ΔG_{{\mathrm{g}} (298.15 \, {\mathrm{K}}, \, 1 \,{\mathrm{atm}})} = (ΔG1 - ΔG2) - (ΔG1^{\prime} - ΔG2^{\prime})\\ = 12.58 \, {\mathrm{kcal}} \,\, {\mathrm{mol}}^{-1}.$$...
Dipak K. Mandal, in Stereochemistry and Organic Reactions, 2021 1.3.4.2 Origin of the torsional strain The origin of the rotational barrier (torsional barrier) has been much debated.11,12 The steric repulsion in the eclipsed conformation is at most a minor factor since the H atoms of the two...