In organic chemistry, syn addition is the addition of two substituents to the same side (or "face") of a double bond or triple bond, resulting in a decrease in bond order but an increase in number of substituents.
In organic chemistry, syn and anti addition are different ways in which two substituents can be added to a double bond or triple bond. Syn addition is the addition of two substituents to the same side (or "face") of a double bond or triple bond, resulting in a decrease in bond order but an increase in number of substituents.