The first iron-catalyzed defluorosilylation of unactivated gem-difluoroalkenes was developed, delivering gemdisilylated alkenes and (E)-silylated alkenes with excellent efficiency.T his protocol features good functional group compatibility and excellent regio-and stereoselectivity,e nabling the late-stage silylation of biologically relevant compounds,t hus providing good opportunities for applications in medicinal chemistry.Preliminary mechanistic studies and DFT calculations reveal that anucleophilic addition and elimination of the second C À Fb ond might be involved in the disilylation catalytic system, demonstrating unusual reactivity characteristics of iron catalysis.Scheme 1. The methods for the synthesis of gem-disilylated alkenes.

Organoboron and organosilane compounds are widely used in organic synthesis and pharmaceuticals. In addition, the C-F bond functionalization is a useful tool for the construction of carbon-carbon and carbon-heteroatom bonds....

The iron-catalyzed construction of Csp 2 −Si bonds via unreactive C−O bonds possesses a challenging topic in organic chemistry. Herein we report an iron-catalyzed silylation of aryl and alkenyl carbamates via C−O bond activation. This protocol features high efficiency and a broad substrate scope, enabling the late-stage silylation of biorelevant compounds and thus providing a good method to access valuable motifs in medicinal chemistry. Moreover, this protocol enables orthogonal transformations of phenol derivatives and also allows for the synthesis of multisubstituted arenes through the carbamate group as the directing group.I ron catalysts have been widely used in cross-coupling reactions owing to their cheapness, abundance, and nontoxicity. 1 To facilitate the oxidative addition in ironcatalyzed cross-coupling reactions, a highly reactive, low-valent iron species always needs to be generated through sacrificial organometallic reagents via reductive elimination in situ. 2 Consequently, these reactions are mostly limited to the formation of C−C bonds through classical cross-coupling reactions, 3 and the iron-catalyzed construction of C− heteroatom bonds has lagged. 4 Organosilicon compounds are important reagents that are widely employed in organic synthesis, material science, as well as medicinal chemistry. 5 However, iron-catalyzed cross-coupling reactions to construct C−Si bonds have been less developed. 6,7 It is of great interest to develop an organometallic reagent-free and efficient ironcatalyzed method for the construction of C−Si bonds.Compared with organohalides, oxygen-based electrophiles, such as phenol and ketone derivatives, have become increasingly more attractive as the coupling partners. 8 Not only are phenols and ketones commercially available and easily produced but also the halide-containing waste is avoided by using oxygen-based electrophiles. The silylation of unreactive C−O bonds has been carried out by the Martin group, 9 but the formation of alkenylsilanes has been less explored. 9b The transmetalation process of silicon nucleophiles is more sluggish than that of other organometallic reagents. To address this issue, metal-based silicon nucleophiles are always used in crosscoupling reactions. For example, pioneering works were reported by the Oshima and Trost groups, 10 in which the aluminum-based silicon reagents were used (Scheme 1). Very recently, Oestreich and coworkers reported the copper-

Herein, we report the iron-catalyzed borylation of aryl ethers and aryl amines via cleavage of C−O and C−N bonds. This protocol does not require the use of Grignard reagents and displays a broad substrate scope, which allows the late-stage borylation. It also provides facile access to multisubstituted arenes through C−H functionalization using 2-pyridyloxy as the directing group.

A ligand-free iron-catalyzed method for the oxygenation of benzylic sp3 C–H bonds by molecular oxygen (1 atm) using a thiyl radical as a cocatalyst has been developed.