Amidophosphine Boranes as Hydroboration Reagents for Nitriles, Alkynes, and Carboxylic Acids

We report here the hydroboration of nitriles, alkynes, and carboxylic acids using amidophosphine boranes {(BH3)(PPh2)-NC(CH3)(3)}, {(BH3)(2)(PPh)(2)N(CH2)C6H5}, and {(BH3)(2)(PPh2)(2)N-(BH3)CH2C6H4N} as reducing agents. These compounds were synthesized to replace more commonly used borane reagents. Solid amidophosphine boranes, which were synthesized with ease, demonstrated excellent reactivity and functional group tolerance toward a wide variety of nitriles, alkynes, and carboxylic acids, affording the corresponding ammonium salts, alkenes, and alcohols in good yield.