THE REACTION BETWEEN FERROCENYLLITHIUM AND TRIMETHYLACETYLCHLORIDE TO FORM EITHER TRIMETHYLACETYLFERROCENE OR 1,1'-BIS(FERROCENYL)-2,2'-DIMETHYLPROPAN-1-OL, AN UNUSUAL HYDROGEN-BONDED DIMER

The addition of ferrocenyllithium, FcLi, to trimethylacetylchloride, Me3CCOCl, yields trimethyl-acetylferrocene, FcCOCMe3, (I), in 77% yield, whereas the reverse addition results in the isolation of 1,1'-bis(ferrocenyl)-2,-2'-dimethylpropan-1-ol, Fc2C(CMe3)OH, (II), a very sterically hindered alcohol, in 62% yield. The conversion of I to II via treatment with FcLi is a facile process occurring in 83% yield. The spectroscopic and structural data on I show it to be less basic than its Si and Ge analogs, but structurally almost identical in terms of C=O bond length etc. The single crystal structural analysis of the alpha-ferrocenylcarbinol (II) shows that it forms discrete cyclic dimers, with the component molecules held together by two symmetrical non-linear hydrogen bonds, a relatively rare type of intermolecular H-bonding.