Organic Chemistry Fundamentals
What you must understand
Recognise functional groups: alkanes, alkenes, alkynes, aromatics, alcohols, ethers, aldehydes, ketones, carboxylic acids, esters, amines, and amides. Apply IUPAC naming rules, including the longest chain, lowest locants, and suffix priorities. Understand structural isomerism, stereoisomerism (geometric and optical), and conformational versus configurational differences. Predict products of substitution, addition, elimination, oxidation, and esterification reactions, and know Markovnikov's rule and the role of carbocation stability. Relate boiling point and solubility to functional groups and hydrogen bonding.
Traps to watch for
- Numbering the chain from the wrong end and giving higher locants.
- Confusing aldehydes and ketones, or esters and ethers, in naming and reactions.
- Forgetting that a carbon with four different groups is chiral and that enantiomers rotate plane-polarised light oppositely.
- Applying Markovnikov's rule without considering peroxide effects in radical additions.
- Treating benzene as alternating single and double bonds rather than delocalised.
Worked example
Name the compound CH3-CH(CH3)-CH2-OH. The longest chain containing the -OH carbon has three carbons, so the parent is propanol. Number from the -OH end to give it the lowest locant, making it carbon 1, and place the methyl on carbon 2. The name is 2-methylpropan-1-ol.
Rule of thumb
Choose the principal functional group by priority (acid > ester > amide > aldehyde > ketone > alcohol > amine), then number to give that group the lowest locant.