Regioselectivity vs. Stereoselectivity

Regioselectivitynoun

(uncountable) The condition of being regioselective.

Regioselectivitynoun

(countable) The degree to which a reaction is regioselective.

Regioselectivity

In chemistry, regioselectivity is the preference of chemical bonding or breaking in one direction over all other possible directions. It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base will abstract from an organic molecule, or where on a substituted benzene ring a further substituent will be added A specific example is a halohydrin formation reaction with 2-propenylbenzene: Because of the preference for the formation of one product over another, the reaction is selective.

Stereoselectivitynoun

(chemistry) The condition of being stereoselective or a measure of the extent to which a reaction is stereoselective

Stereoselectivity

In chemistry, stereoselectivity is the property of a chemical reaction in which a single reactant forms an unequal mixture of stereoisomers during a non-stereospecific creation of a new stereocenter or during a non-stereospecific transformation of a pre-existing one. The selectivity arises from differences in steric effects and electronic effects in the mechanistic pathways leading to the different products.