Synthesis of an osmafuran from photochemical hydrolysis of OsCl2(CHC(PPh3)C(O)-η2-CHCH2)(PPh3)2

The η2-alkene coordinated α,β-unsaturated ketone complex Os(CHC(PPh3)C(O)-η2-CHCH2)Cl2(PPh3)2 (3) is very stable even at elevated temperature due to the strong steric hindrance effect of PPh3 ligands. However, compound 3 in a chloroform solution can be almost quantitatively converted into the corresponding osmafuran [OsCl(CO)(PPh3)2(CHC(PPh3)C(CH3)O)]Cl (6) via hydrolysis of the η2-coordinated olefin under photochemical conditions. Osmafuran 6 has been characterized by single crystal X-ray diffraction analysis, NMR spectroscopy and elemental analysis data. The UV-induced reaction provides a new highly efficient method for preparation of osmafurans by hydrolysis of η2-α,β-unsaturated ketone complexes.

The η2-alkene coordinated α,β-unsaturated ketone complex 1 which is very stable even at elevated temperature can be converted to the corresponding osmafuran 2 almost quantitatively by ultraviolet irradiation. This new highly efficient method for the preparation of osmafurans via photochemically assisted hydrolysis of η2-α,β-unsaturated ketone complexes, presents an addition to previous synthetic approaches.Figure optionsDownload as PowerPoint slide