Highly dispersed WO_m enables efficient reductive debenzylation of hexabenzylhexaazaisowurtzitane (HBIW) over bifunctional Pd-WO_m/CeO₂

The Pd-catalyzed N-debenzylation of hexabenzylhexaazaisowurtzitane (HBIW) to tetraacetyldibenzylhexaazaisowurtzitane (TADBIW) has provided high yields (up to 90.0 %, 12 h) in batch reactors, however, several phase transition stages during the catalytic process disable the development of a continuous flow system. In this work, we designed Pd-WO_m bifunctional catalysts (Pd-WO_m/MO_n) for such a transformation under three-phase reaction conditions with high efficiency. Remarkably, TADBIW was obtained with a high yield of 82.5 % upon reacting for 6 h at 40 °C on Pd-WO_m(5.0)/CeO₂ (Pd: 1.33 mol%). Experimental studies combined with theoretical analysis reveal the HBIW-to-TADBIW conversion is a stepwise hydrogenolysis-acetyldebenzylation process, wherein the initial hydrogenolysis of Ac₂O turn over the catalysis. Importantly, the presence of highly dispersed WO_m domains with proper size not only facilitates hydrogen spillover from Pd site to the adsorpted Ac₂O but also accelerates the subsequent dissociation of *Ac₂O(H), enabling reduction of the overall energy barrier for debenzylation.