Trivalent Zirconium and Hafnium Metal-Organic Frameworks for Catalytic 1,4-Dearomative Additions of Pyridines and Quinolines.

ABSTRACT

We report the quantitative conversion of [MIV6(µ3-O)4(µ3-OH)4Cl12]6- nodes in the MCl2-BTC metal-organic framework into the [MIII6(µ3-O)4(µ3-ONa)4H6]6- nodes in MIIIH-BTC (M = Zr, Hf; BTC is 1,3,5-benzenetricarboxylate) via bimetallic reductive elimination of H2 from putative [MIV6(µ3-O)4(µ3-OH)4H12]6- nodes. The coordinatively unsaturated MIIIH centers in MIIIH-BTC are highly active and selective for 1,4-dearomative hydroboration and hydrosilylation of pyridines and quinolines. This work demonstrated the potential of secondary building unit transformation in generating electronically unique and homogeneously inaccessible single-site solid catalysts for organic synthesis.