Highly efficient and excellent reusable catalysts of molybdenum(VI) complexes grafted on ZPS-PVPA for epoxidation of olefins with tert-BuOOH

Polyoxometalate-based homochiral metal-organic frameworks for tandem asymmetric transformation of cyclic carbonates from olefins

Currently, great interest is focused on developing auto-tandem catalytic reactions; a substrate is catalytically transferred through mechanistically distinct reactions without altering any reaction conditions. Here by incorporating a pyrrolidine moiety as a chiral organocatalyst and a polyoxometalate as an oxidation catalyst, a powerful approach is devised to achieve a tandem catalyst for the efficient conversion of CO₂ into value-added enantiomerically pure cyclic carbonates. The multi-catalytic sites are orderly distributed and spatially matched in the framework. The captured CO₂ molecules are synergistically fixed and activated by well-positioned pyrrolidine and amine groups, providing further compatibility with the terminal W=O activated epoxidation intermediate and driving the tandem catalytic process in a single workup stage and an asymmetric fashion. The structural simplicity of the building blocks and the use of inexpensive and readily available chemical reagents render this approach highly promising for the development of practical homochiral materials for CO₂ conversion.

Using a single catalyst to promote multiple distinct reactions without alteration in reaction conditions is an attractive synthetic goal. Here, to this end, the authors have developed a polyoxometalate-based metal-organic framework for the synthesis of cyclic carbonates from olefins.