I know that most of my chemistry related topics tend to be on very new reports, with this one I am going back a few years (okay, only to 2005...) to a report by Seth Brown et al. (DOI:10.1021/ja055598v) describes “Electronic Dissymmetry”. Asymmetric induction is often attributed to steric interactions between one chiral fragment and one achiral (or another chiral) fragment. This report describes, what the authors believe to be induction through electronics, rather than sterics.

The titanium bisacetylacetonate displayed below is key in the description as electronic structure calculations (B3LYP/6-31G(d)) show that the dz² orbital is “tipped”. Now, when interacting with a molecule such as BINOL (represented by the butane looking structures at left below), there is a clear preference for one orientation over another.



If the titanium bisacetylacetonate BINOL complex is formed, a diastereomeric ratio of > 100:1 in preference of the “matched” isomer is observed (if formed below 5 °C). Although this paper is only a two page communication, it is full of very interesting information, and well worth a read. In a brief conversation with Seth Brown, he mentioned a proclivity to apply classic physical organic methods to inorganic systems, and I think this is a good illustration (and hence the title).