α-C-H Functionalization of π-Bonds Using Iron Complexes: Catalytic Hydroxyalkylation of Alkynes and Alkenes.

The discovery of catalytic systems based on earth-abundant transition metals for the functionalization of C-H bonds enables streamlined and sustainable solutions to problems in synthetic organic chemistry. In this Communication, we disclose an iron-based catalytic system for the functionalization of propargylic and allylic C-H bonds. Inexpensive and readily available cyclopentadienyliron(II) dicarbonyl complexes were employed as catalysts for a novel deprotonative activation mode for C-H functionalization, an approach that allows for the direct union of unsaturated building blocks with aryl aldehydes and other carbonyl electrophiles to deliver a range of unsaturated alcohol coupling products under operationally simple and functional group tolerant reaction conditions.