Answer:Kindly find the structure of A and B in attachment.
Explanation:
Lindlars catalyst is basically a palladium metal based catalyst which reduces specifically the alkynes to just alkenes and only reduce them in cis manner.
The palladium catalyst is poisoned by lead or quinoline so that the reduction reaction can be stopped at a point when alkynes are just reduced to alkenes because palladium in presence of hydrogen reduces the alkyne completely to alkane.
So lindlars catalys is very specific in its action and even in terms of stereochemistry as it only reduces alkynes to alkenes and the stereochemistry of reduced alkyne is cis.
The general formula of lindlars catalyst is : 5%Pd-CaCO3,Pb(OCOCH3)2 and quinoline.
A chiral alkyne would have all 4 different substituents present at the carbon next to triple bond.
since the reduction of chiral alkyne A would be done using Lindlars catalyst hence the reduced product formed would have Cis -stereochemistry.
The structures of A&B are drawn in attachments. Kindly find in attachment.
