Ruthenium-Porphyrin-Based Metal-Organic Frameworks as Recyclable Heterogeneous Catalysts for Carbene Transfer Reactions

Abstract

Ruthenium(II) porphyrin complexes have robust catalytic activity towards various atom and/or group transfer reactions. In order to develop the next generation of practical catalytic systems suitable for organic synthesis in industrial scale, we have prepared a series of rutheniumporphyrin-based metal-organic frameworks (MOFs), and their heterogeneous catalytic properties towards carbene transfer reactions were studied. Among the 5 ruthenium(II)-porphyrin-based MOFs prepared, Ru-MOF-Zr showed the best stability under ambient conditions, and the best catalytic activity towards intermolecular cyclopropanation of styrene derivatives with ethyl diazoacetate (EDA). Compared to its homogeneous counterpart, the heterogeneous Ru-MOF-Zr excels in terms of (1) easy separation from the reaction mixture; (2) recyclability of the catalyst; and (3) size selectivity of the styrene substrates brought by the finite-sized pores of the MOF structure. The same catalyst was also active towards intramolecular cyclopropanation of allylic diazoacetates and diazo coupling reactions. References 1. Zhou, C.-Y.; Huang, J.-S.; Che, C.-M. “Ruthenium-Porphyrin-Catalyzed Carbenoid Transfer Reactions” Synlett 2010, 2681-2700. 2. Che, C.-M; Lo, V. K.-Y.; Zhou, C.-Y.; Huang, J.-S. “Selective Functionalization of Saturated C–H Bonds with Metalloporphyrin Catalysts” Chem. Soc. Rev. 2011, 40, 1095-1975.