What is syn and anti addition?

An addition reaction of an alkene or an alkyne in which the net reaction is addition of two ligands to the multiple-bonded carbon atoms from the same face of the multiple bond is called a syn addition; one in which the net reaction is addition of the two ligands from the opposite faces of the multiple bond is called an …

How do you know if its anti addition or Syn?

When both atoms/groups add to the same face it’s considered syn addition. When they add to opposite faces it’s considered anti addition. The difference between the two is determined by which atom the group added to (Mark vs Anti-Mark) or to which SIDE it adds (syn vs anti).

What is the meaning of syn addition?

Syn addition: An addition reaction in which all new bonds are formed on the same face of the reactant molecule.

What is anti addition of bromine?

Description: Treatment of alkenes with bromine (Br2) gives vicinal dibromides (1,2-dibromides). Notes: The bromines add to opposite faces of the double bond (“anti addition”). Sometimes the solvent is mentioned in this reaction – a common solvent is carbon tetrachloride (CCl4).

What is anti in chemistry?

Anti: Atoms, groups, or other portions of a molecule that point in opposite directions. These entities have a dihedral angle of more than 90o. The two methyl groups are anti and staggered in the anti-periplanar conformation of butane.

Is addition of HCl syn or anti?

In reactions 1 and 3 the elements of HCl add to opposite sides of the double bond. This is called anti addition. The stereochemistry of reaction 4 is also anti. In reaction 5 the elements of deuterated acetic acid add to the same side of the double bond in what is referred to as syn addition.

What is the difference between syn addition and anti addition to a double bond?

The main difference between syn and anti addition is that syn addition involves the addition of substitutes to the same side of the double bond or triple bond whereas anti addition involves the addition of substitutes to the opposite sides of the double bond or triple bond.

What is syn and anti elimination?

In syn elimination, the base attacks the β-hydrogen on the same side as the leaving group. In anti elimination, the base attacks the β-hydrogen on the opposite side of the leaving group. It has been experimentally determined that E2 elimination occurs through an anti mechanism.

Which reaction in alkyne gives anti addition?

However, there are two specific reactions among alkynes where anti-Markovnikov reactions take place: the radical addition of HBr and Hydroboration Oxidation reactions. For alkynes, an anti-Markovnikov addition takes place for terminal alkynes.

Is h2 addition syn or anti?

Hydrogenation Of Alkenes With Pd-C and H2 Is Selective For “Syn” Addition Stereochemistry. Notice how the only product of this reaction is the one where two hydrogens have added to the same face of the alkene (“syn” stereoselectivity). The product where hydrogens add to opposite faces is not observed.

What does anti mean in stereochemistry?

on opposite sides
In the representation of stereochemical relationships “anti” means “on opposite sides” of a reference plane, in contrast to “syn” which means “on the same side”, as in the following examples.