Cucurbit[7]uril-Catalyzed Controllable Pinacol Rearrangement with Activated Hydride Migration

A selective pinacol rearrangement of hydrobenzoin compounds was established through a heterogeneous catalysis strategy in the presence of cucurbit[7]uril. As an unexpected consequence, the ketone was generated as the sole product with the cucurbit[7]uril-controlled hydride migration under optimized conditions. The five recycled runs suggested the catalytic activity of the cucurbit[7]uril remained. The experimental analysis and DFT calculation disclosed the important role of supramolecular encapsulation of substrates within the cavity of the macrocyclic host to fix the phenyl groups on hydrobenzoin compounds and trigger the hydride migration, therefore, ketone was the prior product.

Automated summary

In this study, a selective pinacol rearrangement of hydrobenzoin compounds was achieved through a heterogeneous catalysis strategy in the presence of cucurbit[7]uril. Unexpectedly, the ketone was generated as the sole product under optimized conditions due to the cucurbit[7]uril-controlled hydride migration. The catalytic activity of cucurbit[7]uril was confirmed through five recycled runs. The experimental analysis and DFT calculation revealed the crucial role of supramolecular encapsulation in fixing the phenyl groups on hydrobenzoin compounds and triggering the hydride migration, leading to the preferential formation of ketone.