A facile IrIII-catalyzed benzylic alkylation of arenes with alcohols has been accomplished via borrowing hydrogen (BH) pathways, and the newly developed spirocyclic NHC IrIII pincer complex (Cat A) serves as an efficient catalyst for this atom-economical and greener transformation. Some drug or bioactive molecules and functional material templates can be easily constructed by this strategy.
A facile benzylic alkylation of indenes and other arenes was developed from readily available primary and secondary alcohols using our newly investigated CCC pincer IrIII catalyst (SNIr−H). Excellent regioselectivity and yield (89 %) of the C3-alkylated indenes were obtained. Additionally, the challenging sp2C-alkylation was readily accomplished. This method could be utilized for the synthesis of the analogs of a histamine H1 receptor antagonist and the functional material template molecule, indeno[2,1-a]indene. A hemilabile IrIII-dihydride intermediate was proposed based on control experiments and previous density functional theory (DFT) calculations for the borrowing hydrogen mechanism and is key to the success of this IrIII catalyst in the reduction of unactivated multi-substituted olefin intermediates.Zum Volltext