Terminal-Selective Functionalization of Alkyl Chains by Regioconvergent Cross-Coupling

Hydrocarbons are still the most important precursors of functionalized organic molecules, which has stirred interest in the discovery of new C-H bond functionalization methods. We describe herein a new step-economical approach that enables C-C bonds to be constructed at the terminal position of linear alkanes. First, we show that secondary alkyl bromides can undergo in situ conversion into alkyl zinc bromides and regioconvergent Negishi coupling with aryl or alkenyl triflates. The use of a suitable phosphine ligand favoring Pd migration enabled the selective formation of the linear cross-coupling product. Subsequently, mixtures of secondary alkyl bromides were prepared from linear alkanes by standard bromination, and regioconvergent cross-coupling then provided access to the corresponding linear arylation product in only two steps.