Synthesis, Spectral Characterization and Crystal Structure of Chlororhodibalamin: A Synthesis Platform for Rhodium Analogues of Vitamin B12 and for Rh-Based Antivitamins B12

Widner FJ,Kieninger C,Wurst K,Deery E,Lawrence AD,Warren M,Krautler B. (2020)

Synthesis

Chlororhodibalamin (ClRhbl), a rhodium analogue of vitamin B₁₂(cyanocobalamin), was prepared in 84% yield by metalation of the metal-free B₁₂ligand hydrogenobalamin using the Rh^I-complex [Rh(CO)₂Cl]₂. ClRhbl was identified and characterized by UV/Vis, circular dichroism, high-resolution mass and heteronuclear NMR spectra. The Rh^III-corrin ClRhbl features the base-on architecture of vitamin B₁₂. X-ray analysis of single crystals of ClRhbl have revealed its detailed 3D-geometry and close structural similarity to the Co^III-analogue chlorocobalamin (ClCbl). ClRhbl is a versatile starting material for the preparation of other rhodibalamins, among them the organometallic derivatives adenosylrhodibalamin and methylrhodibalamin, the Rh analogues of the important coenzyme and cofactor forms of B₁₂, adenosylcobalamin and methylcobalamin.

Synthesis

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