Convenient Synthesis of 1 H ‐Indol‐1‐yl Boronates via Palladium(0)‐Catalyzed Borylation of Bromo‐1 H ‐indoles with ‘Pinacolborane’

An atom‐economic Pd 0 ‐catalyzed synthesis of a series of pinacol‐type indolylboronates 3 from the corresponding bromoindole substrates 2 and pinacolborane (pinBH) as borylating agent was elaborated. The optimal catalyst system consisted of a 1 : 2 mixture of [Pd(OAc) 2 ] and the ortho ‐substituted biphenylphosphine ligand L‐3 ( Scheme 4, Table ). Our synthetic protocol was applied to the fast, preparative‐scale synthesis of 1‐substituted indolylboronates 3a – h in the presence of different functional groups, and at a catalyst load of only 1 mol‐% of Pd.