Give the structures and IUPAC names of all the C5H11 alkyl groups, and identify them as pr...

Give the structures and IUPAC names of all the C₅H₁₁ alkyl groups, and identify them as primary, secondary, or tertiary, as appropriate.

Sample Solution Consider the alkyl group having the same carbon skeleton as (CH₃)₄C. All the hydrogens are equivalent; replacing any one of them by a potential point of attachment is the same as replacing any of the others.

Numbering always begins at the point of attachment and continues through the longest continuous chain. In this case the chain is three carbons and there are two methyl groups at C-2. The IUPAC name of this alkyl group is 2,2-dimethylpropyl. (The common name for this group is neopentyl.) It is a primary alkyl group because the carbon that bears the potential point of attachment (C-1) is itself directly bonded to one other carbon.