Which reagent is useful for conversion of alkyne to cis alkene?

Lindlar catalyst
To convert an alkyne to a cis-alkene, we carry out catalytic hydrogenation reaction using what is known as a ‘Lindlar catalyst” – finely powdered palladium deposited on calcium carbonate and modified with lead salts and quinoline.

How could an alkyne be hydrogenated cis selectively by catalytic hydrogenation?

Since alkynes adsorb more strongly to such catalytic surfaces than do alkenes, they preferentially occupy reactive sites on the catalyst. Subsequent transfer of hydrogen to the adsorbed alkyne proceeds slowly, relative to the corresponding hydrogen transfer to an adsorbed alkene molecule.

What does Lindlar’s catalyst do to alkynes?

A less efficient catalyst, Lindlar’s catalyst permits alkynes to be converted to alkenes without further reduction to an alkane. Lindlar’s Catalyst transforms an alkyne to a cis-alkene because the hydrogenation reaction is occurring on the surface of the metal.

Why are alkenes and alkynes important?

Alkenes and alkynes are useful reagents in polymer synthesis—an important industrial application. Hydrogenation reactions typically employ a metallic catalyst consisting of platinum, nickel, palladium, or rhodium.

Why do alkenes undergo addition reaction?

Alkenes are unsaturated molecules, which means they do not have all the hydrogen they could have. This is because there is at least one double bond between carbons. This is a stable structure, but not the most stable, so when certain compounds or elements are added, like fluorine, they undergo an addition reaction.

Why do alkenes and alkynes undergo addition reactions?

Explanation: Alkenes and alkynes are unsaturated – they have π -bonds, so don’t have the full number of hydrogen that they could have. The alkenes and alkynes want to form more σ -bonds and have a structure more like an alkane, so they undergo addition reactions.