Borrowing hydrogen in the activation of alcohols

Alcohols can be temporarily converted into carbonyl compounds by the metal-catalysed removal of hydrogen. The carbonyl compounds are reactive in a wider range of transformations than the precursor alcohols and can react in situ to give imines, alkenes, and alpha-functionalised carbonyl compounds. The metal catalyst, which had borrowed the hydrogen, then returns it to the transformed carbonyl compound, leading to an overall process in which alcohols can be converted into amines, compounds containing C-C bonds and beta-functionalised alcohols.