Cyclohexane: Boat Form Revisited

Abstract

Organic chemistry textbooks often cite an outdated structure for the boat conformer of cyclohexane that is based on ideal bond angles and distances. Density functional computations carried out at the B3LYP/6-311++G(2d,p) level on this conformer show that the structure is more open than previously supposed, with a flagpole H-H distance of 2.35 A. As a consequence, the high energy of this transition state is better attributed to the eclipsed butane torsion interactions and flagpole C-C nonbonded interactions.