Curtin-Hammet principle

Define the Curtin-Hammet principle and use it to predict the expected trans/cis product ratio in the following example:



```
       PhCH2CH(Ph)OCOR    strong base     PhCH=CHPh
                              100C     

```

This part-Q (12-marks) did not include any numerical data. The student is, presumably, required to derive the Curtin-Hammet equation; which, establishes the trans/cis product proportions in terms of their respective transition-state (free energies of activation) energies. But without numerical data how is the trans/cis ratio to be determined?


It may be interesting to note that stilbene, in uv light, undergoes a cis-trans isomerism-equilibrium. So, given such circumstances, the trans/cis ratio must be 50:50? Such a convenient short-cut may not have been required; nor, would it earn the 12-marks. 


