Hindered Rotation of the Isopropenyl Group in Substituted Isopropenylcyclohexanes and Identification of Preferred Rotamers by Nuclear Magnetic Resonance. Bent Bonds May Better Bonds

Article abstract of DOI:10.1021/jo00156a002

The series of 2,2,6,6-tetramethyl-1-isopropenylcyclohexenes 2-6 shows hindered rotation of the isopropenyl group, the activation barrier ΔG(excit.) varying from 12.8 to >15.7 kcal/mol.Splitting patterns and chemical shifts of the olefinic protons of the i