Question

Which of the following reagents should be used to convert hex-3-yne to (Z)-hex-3-ene?

A) H2, Pt
B) Na, NH3
C) H2, Lindlar's catalyst
D) H2SO4, H2O
E) HgSO4, H2O

Answer 1

The reagent to convert hex-3-yne to (Z)-hex-3-ene is C) H2, Lindlar's catalyst. This catalyst ensures partial hydrogenation of the alkyne, leading to the Z-isomer of the alkene without fully reducing it to an alkane. option c is correct.

Step-by-step explanation:

To convert hex-3-yne to (Z)-hex-3-ene, the most suitable reagent would be C) H2, Lindlar's catalyst. Lindlar's catalyst is used for the partial hydrogenation of alkynes to alkenes, and specifically produces the Z-isomer (also known as the cis-isomer) of the double bond.

This type of catalyst is a deactivated palladium catalyst that reduces the alkyne to an alkene without going further to create an alkane, preserving the double bond and controlling the stereochemistry of the product. Other reagents like H2 with Pt, Pd/C, or Ni are typically used for full hydrogenation to form alkanes, while sodium in liquid ammonia (Na, NH3) would lead to the formation of the E-isomer (trans-isomer) of the alkene.