Today, alcohols as building blocks for synthesis go beyond ether and ester formation. Photochemistry and electrochemistry activate the carbon-oxygen bond to form carbon-carbon bonds and carbon-boron bonds for cross-coupling reactions.
Alcohols are the most common commercially available alkyl fragment (Figure 1, top left). Therefore, methods to activate the C–O bond would benefit both industry and academia by providing a vast library of alkyl coupling partners. However, the reactivity of hydroxy groups has classically been limited to nucleophilic attack of various electrophilic moieties by the O atom, for instance esterification and SN2 type reactivity.
Bar chart showing the relative commercial availability of various alkyl synthons (top left); a comparison between bond dissociation energies of C–O and C–Br bonds (top right); the Chugaev elimination and Barton-MacCombie reaction (bottom).
