Towards Selective C-H Oxidation with Aerobically Generated Hypervalent Iodine Reagents

Abstract

Enzymatic hydrocarbon oxidation allows for the selective late-stage functionalization of complex molecules by utilizing O^2 as the terminal oxidant. We are interested in the development of abiological systems that enable functionalization of complex organic molecules using O^2 by utilizing metal-organic framework (MOF) catalysts to effect selective C–H oxidation and to combine this with the environmentally friendly generation of hypervalent iodine reagents, commonly used oxidants in MOF catalysis. To reach this long-term goal, there are fundamental studies that must be addressed. In order to access the pore space of a porous material for selective catalysis, the rates of substrate diffusion and catalytic reaction must be considered. Thus, it is necessary to understand what is known of the diffusion processes relevant to porous materials and methods for probing the relative rates of catalytic reactions to diffusion. In this vein, we investigate the use of cis-decalin as a stereochemical probe for differentiating interstitial from interfacial catalysis for C–H oxidation reactions for porphyrinic metal-organic frameworks. In addition, we examine the effect particle size has on oxidation selectivity and further optimize reaction conditions for the selective oxidation of 1,4-cisdimethylcyclohexane by 2-D layered porphyrinic materials. Lastly, we initiate investigations of coupling the generation of hypervalent iodine chemistry with MOF catalysis by first analyzing the reactivity of hypervalent iodine reagents with soluble analogues of the metalloclusters that serve as secondary building units in MOFs.