Question

Click the "draw structure" button to launch the drawing utility. Draw the structure of the major organic product isolated from the reaction of 3-hexyne with hydrogen (1 mol), Lindlar palladium.

Answer 1

Answer:

cis-hex-2-ene as produced as major product.

Explanation:

• In presence of $Pd/BaSO_{4}$ (Lindlar catalyst) and $H_{2}$, alkynes are reduced to alkene.
• $H_{2}$ molecules first adsorbed onto metal surface through chemisorption.
• When alkyne molecule comes in close proximity to the metal surface, H atoms add onto triple bond to reduce it to alkene.
• Two H atoms add onto alkyne from same face of metal. So, (Z) or cis-isomer of alkene is produced as a major product.
• Reaction mechanism has been shown below.