Electron deficient borane-mediated hydride abstraction in amines: stoichiometric and catalytic processes

The manipulation of amino C-H bonds has garnered significant interest from the synthetic community due to its inherently high atom, step and redox economy. This Tutorial Review summarises the ability of boranes to mediate hydride abstraction from α-amino and γ-amino conjugated C-H bonds. Borane-mediated hydride abstraction results in the generation of reactive iminium hydridoborate salts that participate in a variety of stoichiometric and catalytic processes. The reactions that have utilised this unusual reactivity include those that manipulate amino scaffolds (including dehydrogenation, racemisation, isomerisation, α- and β-functionalisation, and C-N bond cleavage) and those that use amine-based reagents (transfer hydrogenation, and alkylation).