Organic reaction

The number of possible organic reactions is basically infinite. However, certain general patterns are observed that can be used to describe many common or useful reactions. Each reaction has a stepwise mechanism that says how it happens, although this detailed description of steps is not always clear from a list of reactants alone.

Organic reactions can be organized into several basic types:

Addition reactions (halogenation, hydrohalogenation, halogenation, hydration)
Elimination reactions (dehydrohalogenation, dehydration)
1. E1 elimination
2. E2 elimination
Substitution reactions
1. SN1 substitution
2. SN2 substitution
3. ES (electrophilic substitution)
4. EAS (electrophilic aromatic substitution)
5. RS (radical substitution)
Redox reactions
1. Oxidation reactions
2. Reduction reactions
Condensation reactions (Nucleophilic addition + Elimination) and hydrolysis
Polymerization reactions
1. Addition polymerization
2. Condensation polymerization
Rearrangement reactions

Some reactions fit into more than one category. For example, some substitution reactions follow an addition elimination pathway.

Here are some common reactions that you may run into in a college organic chemistry course: addition of HX to an alkene, halogen addition reaction, halohydrin formation reaction, oxymercuration reaction, hydroboration-oxidation reaction, dihydroxylation, ozonolysis, nucleophilic substitution, free radical halogenation, hydration and dehydration.

Here is a series of reactions that a chemist can perform to change molecules in a defined way: Beckmann rearrangement, Friedel-Crafts alkylation and acylation, Gilman reagent, Grignard reagent, Diels-Alder reaction, Pinner reaction, Sharpless epoxidation, Sharpless bishydroxylation, Swern oxidation

As seen here, specific reactions are sometimes named after the chemist who developed them.

(When adding to this page, if a reaction has a common name, please include it at the BEGINNING of the line, for consistency. If the reaction consists of multiple steps, include all steps on a single line, separated by a semicolon.)

Reactions, by reactants: aliphatic compounds

Hydrocarbons

Alkanes (R)

(RS) Free radical halogenation	alkane + X2	→	alkyl halide + HX
Combustion	alkane + O2	→	CO2 + H2O + heat
Cracking	alkane	?? →	2 short alkanes

Alkenes (R=R), Dienes (R=R=R), and Alkynes (R≡R)

(EA) Catalytic addition of hydrogen	(alkene or alkyne) + H2	/[Pt] →	alkane
(EA) Diels-Alder reaction	conjugated diene + dienophile (in heat)	→	cycloalkene
(EA) Alkylation (step 1...)	terminal alkyne + strong base (:B-)	→	acetylide ion
(...step 2)	acetylide ion + alkyl halide	→	longer alkyne
(EA) addition of HX to an alkene	alkene or alkyne + hydrogen halide	→	alkyl halide
(EA)	alkene or alkyne + Cl2 or Br2	→	alkyl dihalide
(EA)	alkene or alkyne + Cl or Br and hydroxide group	→	alkyl halide (Markovnikov's rule)
(EA) oxymercuration reaction	alkene in H₂O / THF with Hg(OAc)₂, and then with NaBH₄,	→	alcohol
(EA) hydroboration-oxidation reaction	alkene or alkyne + B2H6/H2O	→	alcohol
(EA)	alkene or alkyne + water on an organo-mercury intermediate	→	alcohol
-	alkene + (KMnO4 or OsO4) and NaHSO3	→	diol
Cleavage	alkyne + O3 or KMnO4	neutral or acidic solution →	2 carboxylic acid
Cleavage	alkene + ozone followed by zinc in acetic acid	→	2 ketones
Cleavage	alkene + KMnO4	neutral or acidic solution →	either 2 ketones or carboxylic acid + ether
-	alkene + ozone	→	aldehyde (will cause the bond to break if there is a vinylic hydrogen)

(RS) Free radical bromination: alkene + N-bromosuccinimide (NDS) → brominated at allylic position, without adding to double bond.

Hydrocarbons plus Group 17 (Halogen)

Alkyl halides (RX)

(SN1)	alkyl halide + nucleophile	→	nucleophile displaces the halogen atom
(SN2)	alkyl halide + nucleophile	→	nucleophile displaces the halogen atom
(E1)	alkyl halide + base	→	alkene (most substituted possible, Zaitsev's rule)
(E2)	alkyl halide + base	→	alkene (most substituted possible, Zaitsev's rule)
(SN2) Williamson ether synthesis	alkoxide + alkyl halide	→	ether
-	Gilman reagent + alkyl halide + THF in basic solution	→	larger alkane + LiBr
Heck reaction	(aryl, benzyl, or vinyl) (halide or triflate) + alkene	→	expanded carbon skeleton
Stille reaction	(aryl, benzyl, or vinyl) (halide or triflate) + stannane	→	expanded carbon skeleton
Suzuki reaction	(aryl, benzyl, or vinyl) halide + organoborane in basic solution	→	expanded carbon skeleton

Hydrocarbons plus Group 16 (Chalcogen)

Oxygen containing compounds

Alcohols (ROH) and Diols (HOROH)

Primary alcohols = SN2
Tertiary alcohols = SN1
Secondary alcohols = SN1 or SN2 (SNX)

Deprotonation	alcohol + strong base	→	alkoxide ion
Protonation	alcohol + strong acid	→	oxonium ion
(EX) dehydration	tertiary alcohol	acid catalyst →	alkene + H2O
(SN1)	secondary alcohol + hydrogen halide	heat →	alkyl halide
(EX) dehydration	alcohol	acid catalyst + heat ↔	alkene + H2O
(EX) dehydration	alcohol + POCl3/pyridine	→	alkene + H2O
(SN1)	tertiary alcohol	acid catalyst →	alkyl halide
(SNX)	alcohol + HBr	heat →	alkyl halide (RBr)
(SNX)	alcohol + HI	heat →	alkyl halide (RI)
(SNX)	alcohol + HCl	ZnCl2/heat →	alkyl halide (RCl)
(SN2)	1 or 2° alcohol + PBr3	/pyridine →	alkyl halide (RBr)
(SN2)	1 or 2° alcohol + PCl3	/pyridine →	alkyl halide (RCl)
(SN2)	1 or 2° alcohol + SOCl2	/pyridine →	alkyl halide (RCl)
(SNX)	alcohol + sulfonyl chloride (TsCl)	→	ROT + sulfonate ester
-	sulfonate ester	→	compound with a new group bonded to the sp3 carbon
Oxidation	primary alcohol or secondary alcohol + oxidizing agent	→	carbonyl
Oxidation	primary alcohol + oxidizing agent (such as pyridinium chloride)	→	aldehyde
Oxidation	secondary alcohols + oxidizing agent	→	ketone
Cleavage	1,2-diol + HIO4/H2O	→	2 carbonyl
Transesterification	ester + alcohol	↔	different ester + different alcohol
-	2 alcohol	→	ether
-	alkene + alcohol	acid catalyst →	ether

Ethers (ROR)

(SNX) Cleavage	ether + HX	heat →	alcohol + RX
(SN1) Cleavage	tertiary ether	acid catalyst →	alcohol + HX (stable)
(SN2) Cleavage	primary ether or secondary ether	acid catalyst →	alcohol + HX (unstable)

Epoxides (R2COCR2)

(SN1) ring-opening	epoxide	acid catalyst →	ring opened at most substituted position
(SN2) ring-opening	epoxide	base catalyst →	ring opened at least sterically hindered position
ring-opening	epoxide + ?	→	ring opened + alcohol
ring opening and rearrangement	arene oxide + ? + ?	→	ring opened + alcohol
(step 1...)	RBr + Mg/diethyl ether	→	RMgBr4 (Grignard reagent)
(...step 2)	epoxide + Grignard reagent	→	long alcohol

Carbonyl derivatives (RCO-)

Aldehydes and Ketones

SNX	aldehyde or ketone + hydride ion or a carbanion	→	???
SNX	aldehyde or ketone + HCN	→	???
SNX	aldehyde or ketone + primary amine	acid catalyst →	Imine
SNX	aldehyde or ketone + secondary amine	acid catalyst →	Enamine
SNX	aldehyde or ketone + alcohol or thiol	acid catalyst →	???
-	aldehyde or ketone + phosphorus ylide	→	alkene
SNX	an A, B unsaturated aldehyde or ketone + HCN/amine/carbanion	→	added to the B carbon

Aldehydes only (RCOH)

Reduction	aldehyde + reducing agent	→	primary alcohols
Oxidation	aldehyde + oxidizing agent (such as potassium permanganate, nitric acid, or chromium oxide)	→	carboxylic acid
Oxidation	aldehyde + Tollens' reagent (Ag₂O in aqueous ammonia)	→	carboxylic acids (without attacking carbon-carbon double bonds)
(step 1...)	aldehyde + alcohol + acid or base	→	hemiacetal
(...step 2)	hemiacetal + alcohol	acid catalyst →	acetal + water
-	aldehyde + water	→	geminal diols
-	aldehyde + HCN	→	cyanohydrins, R-C(H)(OH)(CN).
-	aldehyde + Grignard reagent	→	alcohol with a substituted group from the Grignard reagent
Wolff-Kishner reaction	aldehyde + hydrazine	→	C=O bond reduced to CH₂
Nucleophilic addition (step 1...)	aldehyde + nucleophile	→	tetrahedral carbonyl addition compound
(...step 2...)	aldehyde + ammonia or primary amine	→	tetrahedral carbonyl addition compound
(...step 3...)	tetrahedral carbonyl addition compound	acid catalyst →	imine + water

Ketones only (RCOR)

Nucleophilic addition	ketone + anion of terminal alkyne	→	tetrahedral carbonyl addition compound (alkoxide)
(...step 2)	alkoxide + aqueous acid	→	hydroxyalkyne
Nucleophilic addition	ketone + ammonia or primary amine	↔	tetrahedral carbonyl addition compound
(...step 2)	tetrahedral carbonyl addition compound	acid catalyst →	imine + water
Nucleophilic addition	ketone + secondary amine	↔	tetrahedral carbonyl addition compound;
(...step 2)	tetrahedral carbonyl addition compound	acid catalyst →	enamine + water
Nucleophilic addition	ketone + Grignard reagent	→	magnesium alkoxide
(...step 2)	magnesium alkoxide + aqueous acid	→	tertiary alcohol
Nucleophilic addition	ketone + organolithium reagent	→	lithium alkoxide
(...step 2)	lithium alkoxide + aqueous acid	→	tertiary alcohol
Nucleophilic addition	ketone + alcohol + acid or base	↔	hemiacetal + water;
(...step 2)	hemiacetal + alcohol	acid catalyst ↔	acetal + water; This is a carbonyl-protecting reaction.
Electrophilic addition	ketone + electrophile	→	resonance stabilized cation
Wittig reaction	ketone' + phosphonium ylide	→	oxphosphetane
(...step 2)	oxphosphetane	→	phosphine oxide + alkene
-	ketone + water	↔	geminal diol
-	ketone + thiol	acid catalyst ↔	thioacetal + water
-	ketone + hydrazine or derivative of hydrazine	→	hydrazone
-	ketone + metal hydride	→	metal alkoxide salt
(...step 2)	metal alkoxide salt + water	→	alcohol
Keto-enol tautomerism	ketone	acid catalyst ↔	enol
(...step 2)	enol + halogen	→	α-haloketone
Reactions at an α-carbon	ketone + aqueous deuterium + D⁺ or OD^- catalyst	→	ketone-d + HOD
Wolff-Kishner reaction	ketone group + hydrazine	↔	methyl group
Clemmensen reduction	ketone group + Zn(Hg), HCl	↔	methyl group

Carboxylic acids (RCOOH)

-	Carboxyl group + amine groups	→	peptide bond
-	Carboxyl group + alcohol	→	ester
Reduction	carboxylic acid + LiAlH4	→	primary alcohol
Deprotonation by base (:B-)	carboxylic acid + H2O/acid or base	→	???
SNX	carboxylic acid + hydride ion	→	alcohol
SNX	carboxylic acid + alcohol	→ Acid catalyst	ester
-	carboxylic acid + thionyl chloride (SOCl2)	→	acid chloride

Esters (R'-COOR")

Reduction	ester + DIBAH	→	aldehyde
SNX	ester + H2O	acid catalyst or base catalyst	carboxylic acid + alcohol
SNX	ester + alcohol	acid catalyst or base catalyst	different ester + different alcohol
SNX	ester + amine	→	???
SNX	ester + hydride ion	→	???
SNX	ester + carbanion	→	???

Acid halides (RCOX)

SRX	acid halide + alcohol	→	ester
SRX	acid halide + amine	→	amide
SRX	acid halide + hydride ion (water)	→	carboxylic acid
SRX	acid halide + carbanion	→	???

Amides (RCONR2)

nucleophilic attack

amide + water

acid catalyst or base catalyst →

carboxylic acid + secondary amine

Sulfur containing compounds

Thiols (RSH)

2 thiols + Hg2+ + Hg2+	→	RS-Hg-SR + 2H+
RS- + R'-Br	→	RSR' + Br-

Sulfides/Thioethers (RSR)

sulfide + R'I	→	RSR'R + I-
RSRR + Y-	→	RY + sulfide

Hydrocarbons plus Group 15 (Pnictogen)

Nitrogen containing compounds

Amines (RNH2)

(SN2) Alkylation	secondary amine + alkyl halide	→	tertiary amine
(SN2) Nucleophilic attack	amine + acid chloride or sulfonyl chloride	→	???
Nucleophilic addition (step 1...)	ketone or aldehyde + ammonia or primary amine	↔	tetrahedral carbonyl addition compound
(... step 2)	tetrahedral carbonyl addition compound	acid catalyst ↔	imine + water

Imines (RC=N)

Nucleophilic addition: (step 1...)	imine + (ammonia or primary amine)	↔	tetrahedral imine addition compound
(...step 2)	tetrahedral imine addition compound	acid catalyst ↔	new imine

Nitriles (RC≡N)

Phosphorus containing compounds

Reactions, by reactants: aromatic compounds

Benzene

(EAS) Friedel-Crafts alkylation	Alkyl Chloride + Aluminium Chloride Catalyst	→	AlkylBenzene
(EAS) Friedel-Crafts acylation	Acyl Chloride	→	AlkylBenzene
(EAS) Halogenation	Bromine + Iron(III)Bromide Catalyst	→	BromoBenzene
(EAS) Halogenation	Chlorine + UV Light	→	ChloroBenzene
(EAS) Nitration	conc. Nitric acid + conc. Sulphuric acid (<55°C)	→	Nitrobenzene
(EAS) Sulfonation	Sulphuric Acid + Sulphur Dioxide or, hot conc. Sulphuric Acid	→	Benzene Sulphonic Acid

External Links

Organic reaction flashcards from OSU (http://www.chemistry.ohio-state.edu/organic/flashcards/)
list of named reactions from UConn (http://orgchem.chem.uconn.edu/namereact/named.html)de:Reaktionsmechanismus

nl:Organische synthese

Retrieved from "https://academickids.com:443/encyclopedia/index.php/Organic_reaction"

Categories: Organic chemistry | Organic reactions