Alcohols & Organometallics (Lecture Notes)

Vocabulary flashcards covering key terms and concepts from the Alcohols and Organometallics lecture notes.

Glycols (1,2-diols)

Compounds with two hydroxyl groups on adjacent carbons; commonly called glycols.

Vicinal diol

Another name for a 1,2-diol; ‘vicinal’ means neighboring (adjacent) carbons.

Polyethylene glycol (PEG)

A polymer of ethylene glycol units; commonly used as a solvent and in food/industrial applications.

Functional-group priority in naming

Rule: if OH is part of a higher-priority class, it is named as hydroxy; priority from highest to lowest: acids, esters, aldehydes, ketones, alcohols, amines, alkenes/alkynes, alkanes, ethers, halides.

Hydroxy as a substituent

The prefix hydroxy is used when the OH group is not the main suffix of the molecule.

Hydrogen bonding

A strong intermolecular interaction that gives alcohols higher boiling points than ethers or alkanes.

Ethylene glycol (ethylene glycol)

A 1,2-diol with formula HO–CH2–CH2–OH; boiling point about 197 °C.

Solubility trend of alcohols in water

Small alcohols are miscible in water; solubility decreases as the alkyl chain length increases.

Phenol vs. cyclohexanol acidity

Phenol is more acidic than cyclohexanol due to resonance stabilization of the phenoxide anion.

pKa range of alcohols

Typical alcohols: pKa ~15.5–18.0 (water ~15.7); phenols around ~10.0; acidity relates to conjugate-base stability.

SN2 and solvolysis in alcohol synthesis

Alcohols can be formed by nucleophilic substitution of alkyl halides (SN2) or by solvolysis where the solvent acts as nucleophile.

Oxymercuration–demercuration

Hydration of alkenes to alcohols via oxymercuration followed by demurcuration; no rearrangements.

Hydroboration–oxidation

Anti-Markovnikov hydration of alkenes to alcohols using borane followed by oxidation.

Syn hydroxylation of alkenes

Formation of vicinal diols by syn addition using OsO4/H2O2 or cold, dilute basic KMnO4.

Anti hydroxylation of alkenes

Formation of vicinal diols by anti addition using peroxyacids followed by hydrolysis.

Reduction of carbonyls to alcohols

Aldehydes/ketones are reduced to primary/secondary alcohols by hydride reagents, forming an alkoxide that is protonated.

Sodium borohydride (NaBH4)

Reduces aldehydes and ketones; generally does not reduce esters or carboxylic acids; requires acid workup to yield alcohol.

Lithium aluminum hydride (LiAlH4)

Stronger reducing agent than NaBH4; reduces aldehydes, ketones, esters, and carboxylic acids to alcohols.

Organometallic reagents in alcohol synthesis

Organometallic reagents (carbon nucleophiles bound to Mg or Li) attack carbonyls to form alcohols and enable C–C bond formation.

Grignard reagents

R–MgX; formed from alkyl halides; ethers stabilize the complex; reactivity: I > Br > Cl > F.

Sodium acetylides

Terminal alkynes converted to sodium acetylides by strong base; nucleophiles that form C–C bonds with alkyl halides or carbonyls.

Addition to carbonyls

Nucleophiles attack the electrophilic carbonyl carbon to form an alkoxide, followed by acidic workup to give an alcohol.

Hydride transfer mechanism (NaBH4/LiAlH4)

Hydride (H−) is transferred to the carbonyl carbon; the resulting alkoxide is protonated to yield an alcohol.

Biological reduction example (NADPH)

In biology, NADPH reduces a ketone (e.g., acetoacetyl ACP to β-hydroxybutyryl ACP) to an alcohol.