Question

Is the hydration of phenylacetylene an anti markovnikov behaviour?

Answer 1

Markovnikov's or Markownikoff's rule defines the result of various additional reactions in organic chemistry. In 1870, Russian scientist Vladimir Markovnikov proposed the rule. The X component is added to the carbon with the fewest hydrogen atoms, whereas the hydrogen atom is added to the carbon with the most hydrogen atoms, according to the rule.

Complete answer:
When an alkene interacts with water to create an alcohol in an additional reaction that involves the production of carbocations, Markownikoff's rule holds true. The hydroxyl group (OH) binds to the carbon with the most carbon–carbon bonds, while the hydrogen links to the carbon with the most carbon–hydrogen bonds on the opposite end of the double bond.
Pathways that do not need a carbocation intermediate, such as free radical addition, may respond by alternative mechanisms with different regioselectivities than those indicated by Markovnikov's rule. Anti-Markovnikov reactions are so named because the halogen adds to the less substituted carbon, which is the polar opposite of a Markovnikov reaction.
No, phenylacetylene hydration is caused by the Markovnikov addition of water over the $C\equiv C$ bond. Gold(I) and gold(III) complexes, as well as mercury(II) ions, catalyse the hydration. The mechanism is complicated, but the end outcome appears to be a Markovnikov addition over the $C\equiv C$ bond.
$\text{PhC}\equiv \text{CH + }{{\text{H}}^{+}}\text{ }\to \text{ Ph}{{\text{C}}^{+}}\text{=CH}\text{ }\to \text{ PhC}\left( \text{OH} \right)\text{=CH}\text{ }\rightleftharpoons \text{ PhC}\left( \text{=O} \right)\text{CH}$
The ${{H}^{+}}$ atom attaches to the C atom with additional hydrogen atoms (the terminal alkyne carbon) to produce the vinyl cation via a Markovnikov addition. After that, the OH joins the cationic carbon to create an enol. The enol tautomerizes to acetophenone, a more stable ketone.

Note:
The production of the most stable carbocation during the addition process is the chemical basis for Markovnikov's Rule. When a hydrogen ion is added to one of the carbon atoms in an alkene, a positive charge is created on the other carbon, producing a carbocation intermediate. Due to induction and hyperconjugation, the more substituted the carbocation is, the more stable it is. The more stable intermediate will produce the majority of the additional reaction's products. As a result, the hydrogen atom is in the less substituted position in the main product of adding HX to an alkene, whereas X is in the more substituted position.