Hydrosilylation of Arynes with Silanes and Silicon-Based Polymer

Benzyne derived from hexadehydrogenated Diels Alder (HDDA) reactions was found to be an efficient hydrosilylation acceptors. Various silanes can react smoothly with HDDA-derived benzyne to give the arylation products. Lewis acid such as boron trifluoride etherate can accelerate these hydrosilylation reactions. Polyhydromethylsiloxane (PHMS), a widely used organosilicon polymer, was also successfully modified using our method. About 5 % of Si-H bonds in the polymer were inserted by benzynes, giving a functional PHMS with much more solubility in methanol and with a blue-emitting fluorescence behavior. Mechanism research shows that the insertion of benzyne into the Si-H bond probably undergoes a synergistic pathway, which is quite different from the traditional radical-initiated hydrosilylation or transition-metal-catalyzed hydrosilylation.

Enantioselective Desymmetrization of Trifluoromethylated Tertiary Benzhydrols via Hydrogen-Acceptor-Free Ir-Catalyzed Dehydrogenative C-H Silylation: Decisive Role of the Trifluoromethyl Group

Although the trifluoromethyl (CF3) group is one of the most important fluorinated groups owing to its significant ability to modulate pharmacological properties, constructing trifluoromethylated stereogenic centers in an enantioselective manner has been a formidable challenge. Herein, we report the development of the enantioselective desymmetrization of trifluoromethylated benzhydrols via intramolecular dehydrogenative silylation using Ir catalysts with chiral pyridine-oxazoline (PyOX) ligands. The produced benzoxasilol was transformed into several unsymmetrical benzhydrols via iododesilylation and subsequent transition-metal-catalyzed cross-coupling reactions. Moreover, the same Ir catalyst system was used for the kinetic resolution of unsymmetrical trifluoromethylated benzhydrols.

Iridium-catalyzed regioselective hydrosilylation of internal alkynes facilitated by directing and steric effects

Here we reported the iridium-catalyzed hydrosilylation of internal alkynes under simple and mild conditions. The intrinsic functional groups of alkyne substrates were disclosed to be crucial in facilitating both the hydrosilylation process and related regioselectivity owing to their coordination capability towards the iridium catalyst. Utilization of the steric trimethylsilyl-protected trihydroxysilane proved to be another critical factor in ensuring the efficient proceeding of this process.

Progress on Iridium-Catalyzed Hydrosilylation of Alkenes and Alkynes

Hydrosilylation of multiple carbon–carbon bonds is a well-known process for the construction of organosilicon compounds. Nowadays, precious metal catalysts, especially platinum complexes, still occupy dominant positions in such processes. However, one important member of the precious metal family, iridium, is less used in this field. As early research mainly focused on developing stable and effective iridium catalysts, recent advances have disclosed the specific efficiency of simple iridium catalytic systems in the synthesis of functional organo­silicon compounds. This short review summarizes the utilization of iridium complexes for the hydrosilylation of alkenes and alkynes, with an emphasis on the recent advances published in the last decade.

1 Introduction

2 Iridium-Catalyzed Hydrosilylation of Alkenes

3 Iridium-Catalyzed Hydrosilylation of Alkynes

4 Conclusions and Perspectives