Give the structure of an optically active alkyne `(A)` having the lowest molecular mass, which on hydrogenatio with Lindlar's catalyst and Birch reduction gives the same lowest molecular mass optically active alkene. Also explain why. ltbr. But alkyne `(A)` on hydrogenation with `D2`, with Lindlar's catalyst, and reduction with `Na+ `liq. `ND_(3)+EtOH` gives a different optically active alkene. Explain.

Explanation

Proceeding in the same manner as in Example , the structure of alkyne `(A)` is `:`

`O.A.` alkyne with the lowest molecular mass.

around `(overset(2)(C)=overset(1)(C))` at `C-2` there are two different groups, `1` there are two same groups , so `(B)` does not show `G.I.`
Hence, the product obtained by two different reactions is the same.

In the above reaction, products `(I)` and `(II)` are different. They are `G.I.` `(` diastereomers `)` because at `C-1` and `C-2` there are two different groups.