What would the following NGP reaction yield?

Question

Question

Attempt I believe that in first reaction there would be simple Sn2. In the second reaction there Should be NGP. Hence i think the products should be diastereomers. But answer is (A)they are enatiomers. How?. Please help.

Answer 1

Reaction-1 is a simple example of an $\mathrm{S_N2}$ reaction, where the acetate group ($\ce{AcO-}$) substitutes the tosyl group ($\ce{OTs}$) forming the product (1) as follows:

But for Reaction-2, the lone pairs present on the $\ce{NMe2}$ provide anchimeric assistance in the removal of the tosyl group, leading to the formation of a bicyclic intermediate (both rings are not coplanar though). The acetate anion can now open the smaller ring in two ways and hence, lead to two different products labelled (1) and (2) as follows:

Finally,to deduce the enantiomeric relation between (1) and (2), the following transformations can be done: