Boriozirconocene Alkanes

However, these compounds proved to be unstable and difficult to characterize. The authors reasoned that the source of the instability was likely to be the trialkylboron moiety. Boronates are more stable than trialkylboranes since the lone-pairs of electrons on an oxygen atom can donate to the empty orbital of a boron atom. The corresponding gem-boriozirconocenes should also be more stable. Thus, hydrozirconation of the alkenyl- 

Zheng et al. [1] postulated that the driving force for plating Zr and B on the same carbon might stem from interactions between the zirconium and oxygen or boron and chlorine atoms. However, an X-ray analysis of 22 revealed that there are no intra- or intermo-lecular interactions between any of these atoms [35]. Compound 22 was also unambiguously characterized by 1H-1H double quantum filtered COSY [36] and C- H heteronuc-lear chemical shift correlation NMR spectroscopy [37,38]. Considerable differences in the chemical shifts of the diastereotopic Cp groups were found in both the H and 13C NMR spectra. The NMR study unequivocally showed that the methine proton was at- 

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Gem boriozirconocene alkanes can be prepared by either hydrozirconation of alkenylboranes or hydroboration of... 

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