In contrast to the many methods of selectively coupling olefins, few protocols catenate saturated hydrocarbons in a predictable manner. We report here the highly selective carbon-hydrogen (C–H) activation and subsequent dehydrogenative C–C coupling reaction of long-chain (>C₂₀) linear alkanes on an anisotropic gold(110) surface, which undergoes an appropriate reconstruction by adsorption of the molecules and subsequent mild annealing, resulting in nanometer-sized channels (1.22 nanometers in width). Owing to the orientational constraint of the reactant molecules in these one-dimensional channels, the reaction takes place exclusively at specific sites (terminal CH₃ or penultimate CH₂ groups) in the chains at intermediate temperatures (420 to 470 kelvin) and selects for aliphatic over aromatic C–H activation.