When determining the integer value of '' (the total number of stereogenic units) to mathematically c — Isomerism and Stereochemistry Chemistry Question
Question
When determining the integer value of '$n$' (the total number of stereogenic units) to mathematically calculate stereoisomers, which of the following specific structural features strictly qualifies as ONE valid stereogenic unit?
💡 Solution & Explanation
A stereogenic unit is defined as a structural site where interchanging two substituents produces a new stereoisomer. A chiral center (with 4 different groups) is one unit, and a restricted rotatory double bond (where each $sp^2$ carbon has two different groups) is also one unit. Terminal alkenes with identical groups and identical tetra-substituted $sp^3$ carbons cannot produce stereoisomers and do not count.