Organic Chemistry Reactions and Mechanisms Review

Comprehensive vocabulary flashcards covering organic chemistry reactions, reagents, mechanisms, and stereochemical outcomes for alkenes, alkynes, alcohols, epoxides, and organometallics.

Markovnikov Addition of HX

An electrophilic addition reaction where a hydrogen halide ($HX$, where $X = F, Br, Cl$) adds across an alkene, directing the halide to the more substituted carbon.

Anti-Markovnikov Addition of HBr

The free-radical addition of $HBr$ across an alkene in the presence of peroxides ($ROOR$), which attaches the bromide to the least substituted carbon (exclusive to $HBr$).

Halide Addition to Alkenes

The addition of elemental halogen ($X_2$, where $X = F, Br, Cl$) in $CH_2Cl_2$ or $CCl_4$ across an alkene, proceeding with anti and coplanar stereospecificity.

Halohydrin Reaction

The reaction of an alkene with $X_2$ and $H_2O$ that yields an anti and coplanar product, placing the hydroxyl group ($OH$) on the more substituted carbon following Markovnikov regiochemistry.

Alkene Formation from Vicinal Dihalide

An $E2$-like dehalogenation of a vicinal dihalide using sodium iodide ($NaI$) or potassium iodide ($KI$) in acetone, eliminating wedges with wedges and dashes with dashes.

Dehydration with H2SO4

An $E1$-like acid-catalyzed elimination of an alcohol using $H_2SO_4$ and heat to form an internal alkene, unable to yield a terminal alkene.

Dehydration with POCl3

An elimination reaction of an alcohol using phosphorus oxychloride ($POCl_3$) and heat that specifically dehydrates to form a terminal alkene.

Direct Acid-Catalyzed Hydration

The addition of water to an alkene using $H_3O^+$ via a carbocation ($C^+$) intermediate, producing a low-yield racemic mixture of alcohols with Markovnikov orientation.

Oxymercuration-Demercuration

A two-step hydration process using 1) $Hg(OAc)_2 / H_2O$ and 2) $NaBH_4$ to add an $OH$ and an $H$ across an alkene with Markovnikov regiochemistry and anti-coplanar stereochemistry without carbocation rearrangement.

Alkoxymercuration-Demercuration

An ether synthesis reaction using 1) $Hg(OAc)_2 / CH_3OH$ (or another alcohol) and 2) $NaBH_4$ across an alkene, proceeding with Markovnikov regiochemistry and anti-coplanar addition.

Hydroboration-Oxidation of Alkenes

A two-step alkene hydration using 1) $BH_3 / THF$ and 2) $H_2O_2 / ^-OH$ that adds $H$ and $OH$ with anti-Markovnikov regiochemistry and syn-planar stereochemistry.

Catalytic Hydrogenation of Alkenes

The reduction of an alkene to an alkane using $H_2$ (or $D_2$) over a $Pt$, $Pd$, or $Ni$ catalyst via syn-planar addition, governed by steric factors.

Glycol Synthesis with OsO4

An alkene oxidation utilizing osmium tetroxide ($OsO_4$) and hydrogen peroxide ($H_2O_2$) to produce a vicinal syn-diol in great yield, though the reagent is expensive and toxic.

Glycol Synthesis with Cold, Basic KMnO4

An alkene oxidation utilizing cold, basic potassium permanganate ($KMnO_4$) to yield a syn-diol; safer and cheaper than $OsO_4$, but gives poorer yield.

Glycol Synthesis via Peroxyacid

The reaction of an alkene with a peracid ($CH_3CO_3H$) and $H_2O$ to produce an anti-diol via an oxirane (epoxide) intermediate.

Ozonolysis of Alkenes

Cleavage of a carbon-carbon double bond using 1) $O_3 / CH_2Cl_2$ and 2) $(CH_3)_2S$ (or $Zn / \text{acetic acid}$) to form aldehydes and ketones, permitting the isolation of formaldehyde.

Warm KMnO4 Alkene Cleavage

Strong oxidative cleavage of an alkene using warm $KMnO_4$ that yields ketones, further oxidizes aldehydes to carboxylic acids, and converts terminal carbons into $CO_2 + H_2O$.

Simmons-Smith Reaction

A cyclopropanation reaction using diiodomethane ($CH_2I_2$) and zinc-copper couple ($Zn(Cu)$) to add a methylene group across an alkene stereospecifically in a syn fashion.

Oxirane Synthesis with mCPBA

The oxidation of an alkene using meta-chloroperoxybenzoic acid ($mCPBA$) in a nonpolar solvent ($CH_2Cl_2$) to form and isolate an epoxide (oxirane).

Acidic Epoxide Opening

The ring opening of an epoxide in the presence of acid ($H^+ / H_2O$ or $ROH$), where the nucleophile attacks the more substituted carbon.

Basic Epoxide Opening

An $S_N2$-like ring-opening reaction of an epoxide under basic conditions ($^-OH$ or $RO^-$) where nucleophilic attack occurs at the least substituted carbon.

Dihalocarbene Addition

The addition of dihalocarbenes (generated from chloroform $CHCl_3$ or bromoform $CHBr_3$ treated with $KOH$) across an alkene to form a gem-dihalocyclopropane ring.

Acetylide Anion

A strong carbon nucleophile ($R-C ≡ C^-$) generated by deprotonating a terminal alkyne with sodium amide ($NaNH_2$), useful for forming carbon-carbon bonds.

Alkyne Synthesis via Double Dehydrohalogenation

Elimination of two equivalents of $HX$ from geminal or vicinal dihalides; using $NaNH_2 / 100^∘\text{C}$ followed by $H_3O^+$ favors terminal alkynes, while $KOH / 200^∘\text{C}$ favors internal alkynes.

Lindlar's Catalyst Hydrogenation

Stereoselective partial reduction of an internal alkyne to a cis-alkene using hydrogen gas ($H_2$) with $Pd(BaSO_4)$ poisoned with quinoline via syn addition.

Dissolving Metal Reduction

Stereoselective reduction of an internal alkyne using sodium metal in liquid ammonia ($Na / NH_3$) to yield a trans-alkene via anti addition of hydrogen.

Mercuric Ion-Catalyzed Alkyne Hydration

Addition of water across an alkyne using $HgSO_4 / H_2O$ and $H_2SO_4$ via Markovnikov addition to yield a ketone (asymmetric internal alkynes produce a mixture).

Hydroboration-Oxidation of Alkynes

The anti-Markovnikov addition of water to a terminal alkyne using 1) disiamylborane ($Sia_2BH$) and 2) $H_2O_2 / ^-OH$ to synthesize an aldehyde.

Mild KMnO4 Alkyne Oxidation

Oxidation of an alkyne with neutral, cold $KMnO_4 / H_2O$ that yields vicinal dicarbonyls from internal alkynes and further oxidizes terminal alkynes to carboxylic acids.

Grignard Reagent

An organomagnesium compound ($R-MgBr$) formed by reacting an alkyl, allyl, vinyl, or aryl halide with magnesium metal ($Mg$) in anhydrous ether.

Corey-House Reaction

A carbon-carbon coupling method in which an organolithium reagent is converted to a lithium dialkylcuprate ($(CH_3)_2CuLi$) with $CuI$ and subsequently coupled with an alkyl halide.

Sodium Borohydride Reduction

A mild hydride reduction method using $NaBH_4$ in ethanol solvent ($EtOH$) that selectively reduces aldehydes and ketones to alcohols.

Lithium Aluminum Hydride Reduction

A strong hydride reduction using 1) $LiAlH_4$ in ether and 2) $H_3O^+$ workup that reduces all carbonyl types (aldehydes, ketones, esters, acid halides, carboxylic acids) to alcohols.

Raney Nickel Reduction

A hydrogenation method using $H_2$ and Raney nickel ($\text{Ra-Ni}$) that simultaneously reduces both alkene double bonds and carbonyl functional groups.

Jones Reagent

An acidic chromium-based oxidizing mixture ($CrO_3 / H_2SO_4 / H_2O$ in acetone at $0^∘\text{C}$) that oxidizes secondary alcohols to ketones and primary alcohols to carboxylic acids.

Pyridinium Chlorochromate (PCC)

A mild oxidant in dichloromethane ($CH_2Cl_2$) capable of oxidizing primary alcohols to aldehydes without over-oxidation to carboxylic acids, and secondary alcohols to ketones.

Tosylate Ester Formation

Reaction of an alcohol with p-toluenesulfonyl chloride ($TsCl$) to produce an alkyl tosylate ($OTos$) with complete retention of stereochemical configuration for subsequent $S_N2$ substitution.

Periodic Acid Cleavage (HIO4)

The oxidative cleavage of vicinal diols into two carbonyl fragments using periodic acid ($HIO_4$); requires the diols to be in a syn configuration.

Williamson Ether Synthesis

An $S_N2$ substitution reaction combining an alkoxide nucleophile ($RO^-$) with an unhindered methyl or primary alkyl halide ($R'-Br$) to produce an asymmetrical or symmetrical ether.

Intermolecular Alcohol Dehydration

Acid-catalyzed condensation of two identical primary alcohol molecules with $H_2SO_4$ at $140^∘\text{C}$ to yield a symmetrical ether and water.

Pinacol-Pinacolone Rearrangement

Acid-catalyzed ($H_2SO_4$) dehydration of a vicinal diol (pinacol) that proceeds via a carbocation intermediate and a 1,2-methyl shift to yield a ketone (pinacolone).

Fischer Esterification

An acid-catalyzed ($H^+$) equilibrium reaction combining a carboxylic acid (or acid halide) and an alcohol to produce an ester and water.