Recent Developments in the Study of NMR Parameters

In certain cases, MM or semiempirical molecular orbital (e.g., MNDO) calculations are useful in predicting Ge chemical shifts. For instance, a variety of t-butylgermacy-clohexanes was prepared and their Ge (when possible) NMR spectra were determined.  

In the case of 1-methyl-1-germacyclohexane derivatives, the Ge chemical shifts are very sensitive to the stereochemistry of a methyl group bonded to germanium. 

that of cis-112 (112ae) is ca. 12 ppm upheld when compared with that of trans-112 (112ee). Hence, it is possible to estimate the ratio of equatorial and Axial isomers of 109 based on its Ge chemical shifts (see Table 12). 

It will be interesting to see if 1-f-butylgermacyclohexanes are also sensitive to the stereochemistry of the f-butyl group and can be a means to distinguish whether 

Reproduced, with permission, from Takeuchi et al., Unresolved. 

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