Cyclopropyl effect causes substituents on cyclohexane to favour axial conformation

Chemists in Canada have uncovered a surprising conformational effect using cyclopropane that provides a way to influence the position of substituents on six-membered rings. Here groups favour the axial orientation, which is usually more unstable, and the effect ‘grows more significant as alkyl groups get larger, which is quite different and unique,’ says James Gleason, who led the work at McGill University. He thinks the ‘really unusual stereocontrol element will be useful in a wide range of applications’, in particular in medicinal chemistry, ‘where the ability to extend groups into specific conformational space is crucial in developing potent molecules.’