Procedure D for the Synthesis of Siloxanes 5. Vinyl silane 4 (1.0 equiv.) was added to a mixture of [Ir(dtbbpy)(ppy)2]PF6 (2.5 mol%) and Bu3N (2.0 equiv.) in dry MeCN/MeOH 9:1 (0.1 M with respect to the silylated product) under Ar. The mixture was degassed 5 min by Ar sparging before placing the reaction vial 1 cm away from the light source. A fan was placed on top of the setup to keep the reaction environment at room temperature. The reaction mixture was irradiated with blue LED light until full consumption of the substrate as indicated by TLC. The mixture was reduced in vacuo, and the crude was purified by column chromatography to afford the wanted siloxane.