Chapter 12: Properties, Synthesis, and Reactions of Alcohols

Vocabulary flashcards covering nomenclature, acidity, synthesis, protecting groups, substitution, elimination, and oxidation reactions of alcohols based on Chapter 12 lecture notes.

-ol Suffix

The IUPAC nomenclature suffix added to the end of the parent alkane chain to identify an alcohol as the principal functional group, using the lowest possible locant number.

Hydroxy

The IUPAC nomenclature prefix used to refer to an $-OH$ group when it is treated as a substituent rather than the principal functional group.

Alkoxide Ion

The conjugate base of an alcohol, produced by deprotonation using sodium hydride ($NaH$) or reactive alkali metals such as $Na$, $Li$, or $K$.

Phenoxide Ion

The conjugate base of phenol ($pKa \thicksim 10$), which is significantly more acidic than aliphatic alcohols due to resonance stabilization that delocalizes the negative charge onto the ortho and para positions of the benzene ring.

Electron-Donating Groups (EDGs)

Substituents on a phenol ring—including p donors (such as $-NH_2$, $-NR_2$, $-OH$, $-OR$) and s donors (alkyl $-R$ or phenyl)—that donate electron density to the ring and decrease phenol acidity.

Electron-Withdrawing Groups (EWGs)

Substituents on a phenol ring—such as halogens, carbonyls, $-SO_3H$, $-CN$, $-NO_2$, $-NR_3^+$, and $-CF_3$—that withdraw electron density, stabilize the phenoxide anion, and increase phenol acidity.

Acid-Catalyzed Hydration of Alkenes

An alkene addition reaction using dilute sulfuric acid ($\text{dil. } H_2SO_4$) that produces an alcohol with Markovnikov regioselectivity through a carbocation intermediate prone to rearrangement.

Oxymercuration-Demercuration

A two-step alkene hydration reaction using $1.\,Hg(OAc)_2,\,H_2O$ followed by $2.\,NaBH_4$ that yields Markovnikov alcohols without carbocation rearrangements.

Hydroboration-Oxidation

A two-step reaction using $1.\,BH_3\cdot THF$ followed by $2.\,H_2O_2,\,NaOH$ that converts alkenes into alcohols via anti-Markovnikov regioselectivity and syn addition.

Anti-Hydroxylation

The reaction of an alkene with a peroxy acid ($RCO_3H$) followed by aqueous acid ($H_3O^+$) to generate a trans-1,2-diol via anti addition.

Syn-Hydroxylation

The reaction of an alkene with osmium tetroxide ($OsO_4$) followed by hydrogen peroxide ($H_2O_2$) to form a 1,2-diol via syn addition across the double bond.

Sodium Borohydride ($NaBH_4$)

A reducing agent that, typically in ethanol ($EtOH$), reduces aldehydes to $1^\text{o}$ alcohols and ketones to $2^\text{o}$ alcohols.

Lithium Aluminum Hydride ($LiAlH_4$)

A strong reducing agent used with an aqueous acid workup ($H_3O^+$) to reduce ketones to $2^\text{o}$ alcohols and aldehydes to $1^\text{o}$ alcohols.

Grignard Reagent

An organomagnesium halide ($R-MgBr$) formed by reacting an alkyl halide with magnesium metal in ether or $THF$, acting as a strong carbon nucleophile that adds to carbonyl compounds to build carbon-carbon bonds.

Trimethylsilyl Chloride (TMSCl)

A protecting group reagent used with triethylamine ($Et_3N$) to convert an alcohol into a trimethylsilyl ether, preventing side reactions with strong bases or Grignard reagents.

Tetrabutylammonium Fluoride (TBAF)

A fluoride-delivering reagent used to deprotect silyl ethers by cleaving the silicon-oxygen bond to regenerate the original alcohol.

Phosphorus Tribromide ($PBr_3$)

A reagent used with pyridine to convert $1^\text{o}$ and $2^\text{o}$ alcohols into alkyl bromides via an $S_N2$ mechanism with inversion of stereochemical configuration.

Thionyl Chloride ($SOCl_2$)

A reagent used in the presence of pyridine to transform $1^\text{o}$ and $2^\text{o}$ alcohols into alkyl chlorides via an $S_N2$ pathway, resulting in inversion of configuration.

Tosylate Ester ($OTs$)

A sulfonate ester prepared by treating an alcohol with p-toluenesulfonyl chloride ($TsCl$) and pyridine, which converts the poor leaving group $-OH$ into a great leaving group with retention of stereochemistry at the carbinol center.

Alcohol Dehydration

An elimination reaction using concentrated sulfuric acid ($\text{conc. } H_2SO_4$) to convert alcohols into alkenes, proceeding via an $E1$ pathway for $2^\text{o}$ and $3^\text{o}$ alcohols and an $E2$ pathway for $1^\text{o}$ alcohols.

Chromic Acid

A strong oxidizing reagent formed from $Na_2Cr_2O_7 / H_2SO_4$, $CrO_3 / H_2SO_4$, or $H_2CrO_4$ that oxidizes $1^\text{o}$ alcohols to carboxylic acids, $2^\text{o}$ alcohols to ketones, and aldehydes to carboxylic acids.

Pyridinium Chlorochromate (PCC)

A mild oxidizing agent that oxidizes $1^\text{o}$ alcohols selectively to aldehydes without further oxidation, and oxidizes $2^\text{o}$ alcohols to ketones.

Chromic Acid Test

A chemical diagnostic test for oxidizable alcohols ($1^\text{o}$ and $2^\text{o}$ alcohols) indicated by an orange-to-green color change as chromium(VI) is reduced.