Study guides › C/P › Organic Chemistry
Alcohols, Ethers & Thiols
Oxygen and sulfur functional groups link alkenes, carbonyls, and halides. You will prepare and oxidize alcohols, build and cleave ethers, open epoxides under acidic and basic conditions, use protecting groups, and compare thiols with alcohols.
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What this chapter covers
- Alcohol Structure, Properties & Acidity. Hydrogen bonding sets alcohol boiling points, and substituent effects set their acidity. Both are common comparison questions.
- Preparing Alcohols. Four routes make most alcohols on the exam: alkene hydration, carbonyl reduction, Grignard addition, and substitution. Match each to its regiochemistry.
- Oxidation of Alcohols & Conversion to Leaving Groups. Choosing PCC versus chromic acid, and knowing the stereochemistry of SOCl₂, PBr₃, and tosylates, is standard MCAT territory.
- Ethers & Epoxides. Epoxide opening under acidic versus basic conditions is one of the highest-yield reaction comparisons in organic chemistry.
- Protecting Groups, Thiols & Disulfides. Protecting groups let you react one site at a time, and thiol chemistry links organic chemistry to cysteine and protein folding.
Key points to know
- Alcohols hydrogen-bond, so they boil much higher than ethers
- Alcohol pKa is about 16, similar to water
- H₃O⁺ and oxymercuration: Markovnikov; hydroboration: anti-Markovnikov, syn
- NaBH₄ reduces only aldehydes and ketones; LiAlH₄ also esters and acids
- PCC stops at aldehydes; aqueous chromic acid goes to acids
- 3° alcohols cannot be oxidized
- Williamson: alkoxide + methyl or primary halide, SN2
- HBr or HI cleaves ethers; aryl ethers give phenol plus alkyl halide
Try a practice question
Which compound has the highest boiling point?
- mol:CCO{ethanol}
- mol:COC{dimethyl ether}
- mol:CCC{propane}
- mol:CCF{fluoroethane}
Show the answer
A. Only ethanol can donate and accept hydrogen bonds. The ether and fluoroalkane have dipoles but no O–H or N–H donor, and propane has only dispersion forces.
Common questions
What does this chapter cover?
Alcohols, Ethers & Thiols covers Alcohol Structure, Properties & Acidity, Preparing Alcohols, Oxidation of Alcohols & Conversion to Leaving Groups, Ethers & Epoxides, Protecting Groups, Thiols & Disulfides.
What should I know first?
Alcohols hydrogen-bond, so they boil much higher than ethers Alcohol pKa is about 16, similar to water H₃O⁺ and oxymercuration: Markovnikov; hydroboration: anti-Markovnikov, syn
24 original practice questions accompany this chapter in the app. Spaced review brings missed ideas back at the right time; it helps memory but cannot promise you will not miss an idea again.