Direct Benzylic C−H Etherification Enabled by Base‐Promoted Halogen Transfer

We disclose a benzylic C−H oxidative coupling reaction with alcohols that proceeds through a synergistic deprotonation, halogenation and substitution sequence. The combination of tert‐butoxide bases with 2‐halothiophene halogen oxidants enables the first general protocol for generating and using benzyl halides through a deprotonative pathway. In contrast to existing radical‐based methods for C−H functionalization, this process is guided by C−H acidity trends. This gives rise to new synthetic capabilities, including the ability to functionalize diverse methyl(hetero)arenes, tolerance of oxidizable and nucleophilic functional groups, precision site‐selectivity for polyalkylarenes and use of a double C−H etherification process to controllably oxidize methylarenes to benzaldehydes. Base‐promoted halogen transfer enables direct benzylic C−H oxidative coupling reactions with alcohols. This new deprotonative C−H oxidation protocol displays unique synthetic capabilities over alternative mechanistic strategies, including the ability to activate high oxidation potential substrates, tolerance of oxidizable and nucleophilic functional groups, and precision site‐selectivity for polyalkylarenes.