Gas phase reactions induced by OH− ion

The site of proton abstraction by OH^? ion in some 4-substituted-3,5,6-triphenyl-Δ′-cyclohexenes has been established from labelling studies. The further fragmentation mode of (M-H)^? ion depends on its structure and stereochemistry. The $\text{exo}$ and $\text{endo}$ nitro isomers exhibit stereochemical differences in the elimination of HNO₂ while the amino and cyano analogues show stereochemically controlled RDA fragmentation mode.