Disiloxane Synthesis Based on Silicon-Hydrogen Bond Activation using Gold and Platinum on Carbon in Water or Heavy Water.

Disiloxanes possessing a silicon-oxygen linkage are important as frameworks for functional materials and coupling partners for Hiyama-type cross coupling. We found that disiloxanes were effectively constructed of hydrosilanes catalyzed by gold on carbon in water as the solvent and oxidant in association with the emission of hydrogen gas at room temperature. The present oxidation could proceed via various reaction pathways, such as the hydration of hydrosilane into silanol, dehydrogenative coupling of hydrosilane into disilane, and the subsequent corresponding reactions to disiloxane. Additionally, the platinum on carbon catalyzed hydrogen-deuterium exchange reaction of arylhydrosilanes as substrates in heavy water proceeded on the aromatic nuclei at 80 °C with high deuterium efficiency and high regioselectivity at the only meta and para positions of the aromatic-silicon bond to give the deuterium-labeled disiloxanes.

Iron-catalyzed ring-opening azidation and allylation of O-heterocycles.

We have established the first catalytic C-C and C-N bond formation reactions of O-heterocycles (e.g., tetrahydrofuran, phthalane, and lactone derivatives) using iron trichloride as a catalyst in the presence of TMSN3 or allylsilanes accompanied by the ring opening of O-heterocycles. The reactions smoothly proceeded at room temperature to give the corresponding primary saturated alcohols from the 2-substituted tetrahydrofurans, ortho-substituted benzyl alcohols from phthalanes, and saturated carboxylic acids from lactones in high yields.