Di-thi-ins (di-"thigh"-ins) are a class of molecules that exhibit this property.
Di-thi-ins (di-"thigh"-ins) are a class of molecules that exhibit this property. This property is possessed by the transition state of an intramolecular reaction which converts a quaternary ammonium salt or sulfonium to an amine or sulfide respectively; that mechanism is the intramolecular Stevens rearrangement. One molecule with this property was first isolated by Donald Cram when he degraded an alpha-pyrone inside a carcerand. That simplest compound with this property acts as both diene and dienophile when it dimerizes through a Diels-Alder reaction at temperatures as low as 35 Kelvin. When analysed by NMR, these molecules exhibit a positive nucleus-independent chemical shift because of their paratropic ring current. By adopting a tub conformation, cyclo-octa-tetra-ene avoids having this property. Cyclo-buta-diene exhibits, for 10 points, what property of cyclic, planar molecules with 4n pi electrons?
Di-thi-ins (di-"thigh"-ins) are a class of molecules that exhibit this property.
antiaromaticity [do not accept or prompt on "aromaticity"]