Question

Give the majore product, when the following compounds are treated with sodium methoxide.


Equaction `(I)` shows no effect with the addition of `Br^(ᶱ)` to the reaction but Eq. (2) shows the common ion effect of `Br^(ᶱ)` if supplied from external source. Why?

Answer 1

There can can be elimination from `2^(o-)` and `3^(@) C^(o+)` to give alkene, and alkene predominates over subsituations in `3^(@) C^(o+)`


Iv. In (i) `Me_(3)C^(o+)` is formed an in (II), `Ph_(3)C^(o+)` is more stable than `Me_(3)C^(o+)` so relative reaction takes place in (II),

Since reaction `(II)` is reversible and it shows common ion effect and equilibrium is shifted to left, so both the products `(Ph_(3)C - OH + Ph_(3)C-Br)` are formed.
But reaction `(I)` is not in equilibrium so common ion effect does not take place, only `Me_(3)C - OH` is formed
v. `(s)-` Bromo propanote ion `underset("High conc.of" overset(o)(O)H)overset(SN^(2))(rarr) (R)-` Lactate ion

The net result of two steps or two inversions is the retension of the configuration.