Hydrolysis of B 2 pin 2 over Pd/C Catalyst: High Efficiency, Mechanism, and in situ Tandem Reaction

A facile and effective synthesis of H 2 or D 2 from Pd/C catalyzed hydrolysis of B 2 pin 2 has first been developed. Among them, B 2 pin 2 is frequently used for borylation reaction, and has rarely been used for hydrogen evolution. The kinetic isotope effects (KIEs) and tandem reaction for diphenylacetylene and norbornene hydrogenation have confirmed both two H atoms of H 2 gas are provided from H 2 O. This is contrary to other boron compounds hydrolysis (including NH 3 BH 3 , NaBH 4 ), which generates H 2 with only one H atom provided by water and the other one by boron compounds. Note that the hydrolysis of B 2 pin 2 in D 2 O also provides an easy and useful synthesis of D 2 .