Hydrosilafluorenes as Recyclable Coupling Reagents for Direct Amidation of Carboxylic Acids with Amines

We have discovered both 9-methyl- and 9-phenyl-9<i>H</i>-9-silafluorene as effective reagents for direct amidation. The protocol is performed under open-air conditions without rigorous exclusion of moisture, producing amides in high yields with only H₂ and disiloxane as byproducts. The disiloxane byproduct can be reduced in a separate step to recycle the silafluorenes. This breakthrough represents the first example of a recyclable organosilane coupling reagent and is a significant step toward developing greener amidating agents.