CHE-300 Review nomenclature syntheses reactions mechanisms

Alkanes Alkyl halides Alcohols Ethers Alkenes conjugated dienes Alkynes Alicyclics Epoxides

Alkanes Nomenclature Syntheses 1. reduction of alkene (addition of hydrogen) 2. reduction of an alkyl halide a) hydrolysis of a Grignard reagent b) with an active metal and acid 3. Corey-House Synthesis Reactions 1. halogenation 2. combustion (oxidation) 3. pyrolysis (cracking)

Alkanes, nomenclature CH3 CH3CH2CH2CH2CH2CH3 CH3CHCH2CH2CH3 (n-hexane) (isohexane) n-hexane 2-methylpentane CH3 CH3 CH3CH2CHCH2CH3 CH3CCH2CH3 (no common name) CH3 3-methylpentane (neohexane) 2,2-dimethylbutane CH3CHCHCH3 (no common name) 2,3-dimethylbutane

Alkanes, syntheses 1. Addition of hydrogen (reduction). | | | | — C = C — + H2 + Ni, Pt, or Pd  — C — C — | | H H Requires catalyst. CH3CH=CHCH3 + H2, Ni  CH3CH2CH2CH3 2-butene n-butane

Reduction of an alkyl halide a) hydrolysis of a Grignard reagent (two steps) i) R—X + Mg  RMgX (Grignard reagent) ii) RMgX + H2O  RH + Mg(OH)X SB SA WA WB CH3CH2CH2-Br + Mg  CH3CH2CH2-MgBr n-propyl bromide n-propyl magnesium bromide CH3CH2CH2-MgBr + H2O  CH3CH2CH3 + Mg(OH)Br propane

with an active metal and an acid R—X + metal/acid  RH active metals = Sn, Zn, Fe, etc. acid = HCl, etc. (H+) CH3CH2CHCH3 + Sn/HCl  CH3CH2CH2CH3 + SnCl2 Cl sec-butyl chloride n-butane CH3 CH3 CH3CCH3 + Zn/H+  CH3CHCH3 + ZnBr2 Br tert-butyl bromide isobutane

3. Corey-House Synthesis CH3 CH3 CH3 CH3CH-Br + Li  CH3CH-Li + CuI  (CH3CH)2-CuLi isopropyl bromide CH3 CH3 (CH3CH)2-CuLi + CH3CH2CH2-Br  CH3CH-CH2CH2CH3 2-methylpentane (isohexane) mechanism = SN2 Note: the R´X should be a 1o or methyl halide for the best yields of the final product.

Alkanes, reactions 1. Halogenation R-H + X2, heat or hv  R-X + HX a) heat or light required for reaction. b) X2: Cl2 > Br2  I2 c) yields mixtures  d) H: 3o > 2o > 1o > CH4 e) bromine is more selective f) free radical substitution

CH3CH2CH2CH3 + Br2, hv  CH3CH2CH2CH2-Br 2% + CH3CH2CHCH3 98% Br n-butane n-butyl bromide + CH3CH2CHCH3 98% Br sec-butyl bromide CH3 CH3 CH3CHCH3 + Br2, hv  CH3CHCH2-Br <1% isobutane isobutyl bromide CH3 CH3CCH3 99% tert-butyl bromide

Alkyl halides nomenclature syntheses 1. from alcohols a) HX b) PX3 2. halogenation of certain alkanes 3. addition of hydrogen halides to alkenes 4. addition of halogens to alkenes 5. halide exchange for iodide reactions 1. nucleophilic substitution 2. dehydrohalogenation 3. formation of Grignard reagent 4. reduction

Alkyl halides, nomenclature CH3 CH3 CH3CHCH2CHCH3 CH3CCH3 Br I 2-bromo-4-methylpentane tert-butyl iodide 2-iodo-2-methylpropane 2o 3o CH3 Cl-CHCH2CH3 sec-butyl chloride 2-chlorobutane 2o

Alkyl halides, syntheses 1. From alcohols With HX R-OH + HX  R-X + H2O i) HX = HCl, HBr, HI ii) may be acid catalyzed (H+) iii) ROH: 3o > 2o > CH3 > 1o (3o/2o – SN1; CH3/1o – SN2) iv) rearrangements are possible except with most 1o ROH

CH3CH2CH2CH2-OH + NaBr, H2SO4, heat  CH3CH2CH2CH2-Br n-butyl alcohol (HBr) n-butyl bromide 1-butanol 1-bromobutane CH3 CH3 CH3CCH3 + HCl  CH3CCH3 OH Cl tert-butyl alcohol tert-butyl chloride 2-methyl-2-propanol 2-chloro-2-methylpropane CH3-OH + HI, H+,heat  CH3-I methyl alcohol methyl iodide methanol iodomethane

CH3CHCH2-OH + PBr3  CH3CHCH2-Br …from alcohols: b) PX3 i) PX3 = PCl3, PBr3, P + I2 ii) ROH: CH3 > 1o > 2o iii) no rearragements CH3CH2-OH + P, I2  CH3CH2-I ethyl alcohol ethyl iodide ethanol iodoethane CH3 CH3 CH3CHCH2-OH + PBr3  CH3CHCH2-Br isobutyl alcohol isobutyl bromide 2-methyl-1-propanol 1-bromo-2-methylpropane

Halogenation of certain hydrocarbons. R-H + X2, Δ or hν  R-X + HX (requires Δ or hν; Cl2 > Br2 (I2 NR); 3o>2o>1o) yields mixtures!  In syntheses, limited to those hydrocarbons that yield only one monohalogenated product. CH3 CH3 CH3CCH3 + Cl2, heat  CH3CCH2-Cl CH3 CH3 neopentane neopentyl chloride 2,2-dimethylpropane 1-chloro-2,2-dimethylpropane

Halide exchange for iodide. R-X + NaI, acetone  R-I + NaX  i) R-X = R-Cl or R-Br ii) NaI is soluble in acetone, NaCl/NaBr are insoluble. CH3CH2CH2-Br + NaI, acetone  CH3CH2CH2-I n-propyl bromide n-propyl idodide 1-bromopropane 1-idodopropane iii) SN2 R-X should be 1o or CH3

Reactions of alkyl halides: Nucleophilic substitution Best with 1o or CH3!!!!!! R-X + :Z-  R-Z + :X- Dehydrohalogenation R-X + KOH(alc)  alkene(s) Preparation of Grignard Reagent R-X + Mg  RMgX Reduction R-X + Mg  RMgX + H2O  R-H R-X + Sn, HCl  R-H

1. Nucleophilic substitution R-X + :OH-  ROH + :X- alcohol R-X + H2O  ROH + HX alcohol R-X + :OR´-  R-O-R´ + :X- ether R-X + -:CCR´  R-CCR´ + :X- alkyne R-X + :I-  R-I + :X- iodide R-X + :CN-  R-CN + :X- nitrile R-X + :NH3  R-NH2 + HX primary amine R-X + :NH2R´  R-NHR´ + HX secondary amine R-X + :SH-  R-SH + :X- thiol R-X + :SR´  R-SR´ + :X- thioether Etc. Best when R-X is CH3 or 1o! SN2

2. dehydrohalogenation of alkyl halides | | | | — C — C — + KOH(alc.)  — C = C — + KX + H2O | | H X RX: 3o > 2o > 1o no rearragement  may yield mixtures  Saytzeff orientation element effect isotope effect rate = k [RX] [KOH] Mechanism = E2

CH3CHCH3 + KOH(alc)  CH3CH=CH2 Br isopropyl bromide propylene CH3CH2CH2CH2-Br + KOH(alc)  CH3CH2CH=CH2 n-butyl bromide 1-butene CH3CH2CHCH3 + KOH(alc)  CH3CH2CH=CH2 Br 1-butene 19% sec-butyl bromide + CH3CH=CHCH3 2-butene 81%

3. preparation of Grignard reagent CH3CH2CH2-Br + Mg  CH3CH2CH2-MgBr n-propyl bromide n-propyl magnesium bromide reduction CH3CH2CH2-MgBr + H2O  CH3CH2CH3 + Mg(OH)Br propane CH3CH2CHCH3 + Sn/HCl  CH3CH2CH2CH3 + SnCl2 Cl sec-butyl chloride n-butane

Alcohols nomenclature syntheses 1. oxymercuration-demercuration 2. hydroboration-oxidation 3. 4. hydrolysis of some alkyl halides reactions 1. HX 2. PX3 3. dehydration 4. as acids 5. ester formation 6. oxidation

Alcohols, nomenclature CH3 CH3 CH3CHCH2CHCH3 CH3CCH3 OH OH 4-methyl-2-pentanol tert-butyl alcohol 2-methyl-2-propanol 2o 3o CH3 HO-CHCH2CH3 CH3CH2CH2-OH sec-butyl alcohol n-propyl alcohol 2-butanol 1-propanol 2o 1o

Alcohols, syntheses 1. oxymercuration-demercuration: Markovnikov orientation. 100% yields.  no rearrangements  CH3CH2CH=CH2 + H2O, Hg(OAc)2; then NaBH4  CH3CH2CHCH3 OH

2. hydroboration-oxidation: Anti-Markovnikov orientation.  100% yields.  no rearrangements  CH3CH2CH=CH2 + (BH3)2; then H2O2, NaOH  CH3CH2CH2CH2-OH

Reaction of alcohols 1. with HX: R-OH + HX  R-X + H2O a) HX: HI > HBr > HCl b) ROH: 3o > 2o > CH3 > 1o SN1/SN2 c) May be acid catalyzed d) Rearrangements are possible except with most 1o alcohols.

CH3CH2CH2CH2-OH + NaBr, H2SO4, heat  CH3CH2CH2CH2-Br n-butyl alcohol (HBr) n-butyl bromide 1-butanol 1-bromobutane CH3 CH3 CH3CCH3 + HCl  CH3CCH3 OH Cl tert-butyl alcohol tert-butyl chloride 2-methyl-2-propanol 2-chloro-2-methylpropane CH3-OH + HI, H+,heat  CH3-I methyl alcohol methyl iodide methanol iodomethane

 With PX3 ROH + PX3  RX PX3 = PCl3, PBr3, P + I2 No rearrangements ROH: CH3 > 1o > 2o CH3 CH3 CH3CCH2-OH + PBr3  CH3CCH2-Br neopentyl alcohol 2,2-dimethyl-1-bromopropane 

Dehydration of alcohols | | | | — C — C — acid, heat  — C = C — + H2O | | H OH ROH: 3o > 2o > 1o acid is a catalyst rearrangements are possible  mixtures are possible  Saytzeff mechanism is E1

CH3CH2-OH + 95% H2SO4, 170oC  CH2=CH2 CH3CCH3 + 20% H2SO4, 85-90oC  CH3C=CH2 OH CH3CH2CHCH3 + 60% H2SO4, 100oC  CH3CH=CHCH3 + CH3CH2CH=CH2 CH3CH2CH2CH2-OH + H+, 140oC  CH3CH2CH=CH2 rearrangement!  + CH3CH=CHCH3

As acids. With active metals: ROH + Na  RONa + ½ H2  CH3CH2-OH + K  CH3CH2-O-K+ + H2 With bases: CH4 < NH3 < ROH < H2O < HF ROH + NaOH  NR! CH3CH2OH + CH3MgBr  CH4 + Mg(Oet)Br

Ester formation. CH3CH2-OH + CH3CO2H, H+  CH3CO2CH2CH3 + H2O CH3CH2-OH + CH3COCl  CH3CO2CH2CH3 + HCl CH3-OH + CH3SO2Cl  CH3SO3CH3 + HCl Esters are alkyl “salts” of acids.

Oxidation Oxidizing agents: KMnO4, K2Cr2O7, CrO3, NaOCl, etc. Primary alcohols: CH3CH2CH2-OH + KMnO4, etc.  CH3CH2CO2H carboxylic acid Secondary alcohols: OH O CH3CH2CHCH3 + K2Cr2O7, etc.  CH3CH2CCH3 ketone Teriary alcohols: no reaction.

Primary alcohols ONLY can be oxidized to aldehydes: CH3CH2CH2-OH + C5H5NHCrO3Cl  CH3CH2CHO pyridinium chlorochromate aldehyde or CH3CH2CH2-OH + K2Cr2O7, special conditions 

Ethers nomenclature syntheses 1. Williamson Synthesis 2. alkoxymercuration-demercuration reactions 1. acid cleavage

Ethers R-O-R or R-O-R´ Nomenclature: simple ethers are named: “alkyl alkyl ether” “dialkyl ether” if symmetric CH3 CH3 CH3CH2-O-CH2CH3 CH3CH-O-CHCH3 diethyl ether diisopropyl ether

1. Williamson Synthesis of Ethers R-OH + Na  R-O-Na+  R-O-R´ R´-OH + HX  R´-X (CH3)2CH-OH + Na  (CH3)2CH-O-Na+ +  CH3CH2CH2-O-CH(CH3)2 CH3CH2CH2-OH + HBr  CH3CH2CH2-Br isopropyl n-propyl ether note: the alkyl halide is primary! 

CH3CH2CH2-OH + Na  CH3CH2CH2-ONa +  CH3CH2CH2-O-CH(CH3)2 (CH3)2CH-OH + HBr  (CH3)2CH-Br 2o The product of this attempted Williamson Synthesis using a secondary alkyl halide results not in the desired ether but in an alkene! The alkyl halide in a Williamson Synthesis must beCH3 or 1o! 

2. alkoxymercuration-demercuration: Markovnikov orientation. 100% yields.  no rearrangements  CH3CH=CH2 + CH3CHCH3, Hg(TFA)2; then NaBH4  OH CH3 CH3 CH3CH-O-CHCH3 diisopropyl ether Avoids the elimination with 2o/3o RX in Williamson Synthesis.

Reactions, ethers: Acid cleavage. R-O-R´ + (conc) HX, heat  R-X + R´-X CH3CH2-O-CH2CH3 + HBr, heat  2 CH3CH2-Br

Alkenes nomenclature syntheses 1. dehydrohalogenation of an alkyl halide 2. dehydration of an alcohol 3. dehalogenation of a vicinal dihalide 4. reduction of an alkyne reactions 1. addition of hydrogen 8. hydroboration-oxidation 2. addition of halogens 9. addition of free radicals 3. addition of hydrogen halides 10. addition of carbenes 4. addition of sulfuric acid 11. epoxidation 5. addition of water 12. hydroxylation 6. halohydrin formation 13. allylic halogenation 7. oxymercuration-demercuration 14. ozonolysis 15. vigorous oxidation

Alkenes, nomenclature C3H6 propylene CH3CH=CH2 C4H8 butylenes CH3CH2CH=CH2 α-butylene 1-butene CH3 CH3CH=CHCH3 CH3C=CH2 β-butylene isobutylene 2-butene 2-methylpropene

* * * * (Z)-3-methyl-2-pentene (3-methyl-cis-2-pentene) (E)-1-bromo-1-chloropropene *

1. dehydrohalogenation of alkyl halides | | | | — C — C — + KOH(alc.)  — C = C — + KX + H2O | | H X RX: 3o > 2o > 1o no rearragement  may yield mixtures  Saytzeff orientation element effect isotope effect rate = k [RX] [KOH] Mechanism = E2

CH3CHCH3 + KOH(alc)  CH3CH=CH2 Br isopropyl bromide propylene CH3CH2CH2CH2-Br + KOH(alc)  CH3CH2CH=CH2 n-butyl bromide 1-butene CH3CH2CHCH3 + KOH(alc)  CH3CH2CH=CH2 Br 1-butene 19% sec-butyl bromide + CH3CH=CHCH3 2-butene 81%

dehydration of alcohols: | | | | — C — C — acid, heat  — C = C — + H2O | | H OH ROH: 3o > 2o > 1o acid is a catalyst rearrangements are possible  mixtures are possible  Saytzeff mechanism is E1

CH3CH2-OH + 95% H2SO4, 170oC  CH2=CH2 CH3CCH3 + 20% H2SO4, 85-90oC  CH3C=CH2 OH CH3CH2CHCH3 + 60% H2SO4, 100oC  CH3CH=CHCH3 + CH3CH2CH=CH2 CH3CH2CH2CH2-OH + H+, 140oC  CH3CH2CH=CH2 rearrangement!  + CH3CH=CHCH3

dehalogenation of vicinal dihalides | | | | — C — C — + Zn  — C = C — + ZnX2 | | X X eg. CH3CH2CHCH2 + Zn  CH3CH2CH=CH2 + ZnBr2 Br Br Not generally useful as vicinal dihalides are usually made from alkenes. May be used to “protect” a carbon-carbon double bond.

4. reduction of alkyne CH3 H \ / Na or Li C = C anti- NH3(liq) / \ \ / Na or Li C = C anti- NH3(liq) / \ H CH3 trans-2-butene CH3CCCH3 H H H2, Pd-C C = C syn- Lindlar catalyst / \ CH3 CH3 cis-2-butene

Alkenes, reactions 1. Addition of hydrogen (reduction). | | | | — C = C — + H2 + Ni, Pt, or Pd  — C — C — | | H H a) Requires catalyst. #1 synthesis of alkanes CH3CH=CHCH3 + H2, Ni  CH3CH2CH2CH3 2-butene n-butane

2. Addition of halogens. | | | | — C = C — + X2  — C — C — | | X X X2 = Br2 or Cl2 test for unsaturation with Br2 CH3CH2CH=CH2 + Br2/CCl4  CH3CH2CHCH2 Br Br 1-butene 1,2-dibromobutane

Addition of hydrogen halides. | | | | — C = C — + HX  — C — C — | | H X HX = HI, HBr, HCl Markovnikov orientation CH3CH=CH2 + HI  CH3CHCH3 I CH3 CH3 CH2C=CH2 + HBr  CH3CCH3 Br

Addition of sulfuric acid. | | | | — C = C — + H2SO4  — C — C — | | H OSO3H alkyl hydrogen sulfate Markovnikov orientation. CH3CH=CH2 + H2SO4  CH3CHCH3 O O-S-O OH

Addition of water. | | | | — C = C — + H2O, H+  — C — C — | | H OH a) requires acid Markovnikov orientation low yield  CH3CH2CH=CH2 + H2O, H+  CH3CH2CHCH3 OH

Addition of halogens + water (halohydrin formation): | | | | — C = C — + X2, H2O  — C — C — + HX | | OH X X2 = Br2, Cl2 Br2 = electrophile CH3CH=CH2 + Br2(aq.)  CH3CHCH2 + HBr OH Br

7. oxymercuration-demercuration: a) Markovnikov orientation. b) 100% yields.  c) no rearrangements  CH3CH2CH=CH2 + H2O, Hg(OAc)2; then NaBH4  CH3CH2CHCH3 OH

With alcohol instead of water: alkoxymercuration-demercuration: | | | | — C =C — + ROH, Hg(TFA)2  — C — C — | | OR HgTFA | | | | — C — C — + NaBH4  — C — C — OR HgTFA OR H ether

8. hydroboration-oxidation: #2 synthesis of alcohols. Anti-Markovnikov orientation.  100% yields.  no rearrangements  CH3CH2CH=CH2 + (BH3)2; then H2O2, NaOH  CH3CH2CH2CH2-OH

9. Addition of free radicals. | | | | — C = C — + HBr, peroxides  — C — C — | | H X anti-Markovnikov orientation. free radical addition CH3CH=CH2 + HBr, peroxides  CH3CH2CH2-Br

10. Addition of carbenes. | | | | — C = C — + CH2CO or CH2N2 , hν  — C — C —  CH2 •CH2• “carbene” adds across the double bond | | — C = C —   •CH2•

11. Epoxidation. | | C6H5CO3H | | — C = C — + (peroxybenzoic acid)  — C— C — O epoxide Free radical addition of oxygen diradical. | | — C = C —   •O•

12. Hydroxylation. (mild oxidation) | | | | — C = C — + KMnO4  — C — C — syn | | OH OH OH — C = C — + HCO3H  — C — C — anti peroxyformic acid | | glycol

stereoselective and stereospecific cis-2-butene + KMnO2  meso-2,3-dihydroxybutane mp 34o CH3 H OH trans-2-butene + KMnO4  (S,S) & (R,R)-2,3-dihydroxybutane mp 19o CH3 CH3 H OH + HO H HO H H OH CH3 CH3 stereoselective and stereospecific

13. Allylic halogenation. | | | | | | — C = C — C — + X2, heat  — C = C — C — + HX | | H  allyl X CH2=CHCH3 + Br2, 350oC  CH2=CHCH2Br + HBr a) X2 = Cl2 or Br2 b) or N-bromosuccinimide (NBS)

14. Ozonolysis. | | | | — C = C — + O3; then Zn, H2O  — C = O + O = C — used for identification of alkenes CH3 CH3CH2CH=CCH3 + O3; then Zn, H2O  CH3CH2CH=O + O=CCH3

15. Vigorous oxidation. =CH2 + KMnO4, heat  CO2 =CHR + KMnO4, heat  RCOOH carboxylic acid =CR2 + KMnO4, heat  O=CR2 ketone

CH3CH2CH2CH=CH2 + KMnO4, heat  CH3CH2CH2COOH + CO2 CH3 CH3 CH3C=CHCH3 + KMnO4, heat  CH3C=O + HOOCCH3

Dienes nomenclature syntheses same as alkenes reactions special: conjugated dienes 1. more stable 2. preferred products of eliminations 3. give 1,2- & 1,4- addition products

(cumulated dienes are not very stable and are rare) isolated dienes are as you would predict, undergo addition reactions with one or two moles…  conjugated dienes are unusual in that they: are more stable than predicted are the preferred products of eliminations give 1,2- plus 1,4-addition products

nomenclature: CH2=CHCH=CH2 CH3CH=CHCH2CH=CHCH3 1,3-butadiene 2,5-heptadiene conjugated isolated 2-methyl-1,3-butadiene (isoprene) conjugated

isolated dienes: (as expected) 1,5-hexadiene CH2=CHCH2CH2CH=CH2 + H2, Ni  CH3CH2CH2CH2CH=CH2 CH2=CHCH2CH2CH=CH2 + 2 H2, Ni  CH3CH2CH2CH2CH2CH3 CH2=CHCH2CH2CH=CH2 + Br2  CH2CHCH2CH2CH=CH2 Br Br CH2=CHCH2CH2CH=CH2 + HBr  CH3CHCH2CH2CH=CH2 Br CH2=CHCH2CH2CH=CH2 + 2 HBr  CH3CHCH2CH2CHCH3 Br Br

conjugated dienes yield 1,2- plus 1,4-addition: CH2=CHCH=CH2 + H2, Ni  CH3CH2CH=CH2 + CH3CH=CHCH3 CH2=CHCH=CH2 + 2 H2, Ni  CH3CH2CH2CH3 CH2=CHCH=CH2 + Br2  CH2CHCH=CH2 + CH2CH=CHCH2 Br Br Br Br CH2=CHCH=CH2 + HBr  CH3CHCH=CH2 + CH3CH=CHCH2 Br Br peroxides CH2=CHCH=CH2 + HBr  CH2CH=CHCH3 + CH2CH2CH=CH2 Br Br

Alkynes nomenclature syntheses 1. dehydrohalogenation of vicinal dihalides 2. coupling of metal acetylides with alkyl halides reactions 1. reduction 2. addition of halogens 3. addition of hydrogen halides 4. addition of water 5. as acids 6. with Ag+ 7. oxidation

Alkynes, nomenclature HCCH ethyne acetylene CH3 CH3CH2CCH HCCCHCH2CH3 1-butyne 3-methyl-1-pentyne ethylacetylene sec-butylacetylene

Synthesis, alkynes: dehydrohalogenation of vicinal dihalides H H H | | | — C — C — + KOH  — C = C — + KX + H2O | | | X X X H | — C = C — + NaNH2  — C  C — + NaX + NH3 X

coupling of metal acetylides with 1o/CH3 alkyl halides R-CC-Na+ + R´X  R-CC-R´ + NaX SN2 R´X must be 1o or CH3X CH3CC-Li+ + CH3CH2-Br  CH3CCCH2CH3

1. Addition of hydrogen (reduction) Alkyne, reactions 1. Addition of hydrogen (reduction) HCCH + 2 H2, Pt  CH3CH3 [ HCCH + one mole H2, Pt  CH3CH3 + CH2=CH2 + HCCH ] H \ / Na or Li C = C anti- NH3(liq) / \ — C  C — \ / H2, Pd-C C = C syn- Lindlar catalyst / \ H H

CH3 H \ / Na or Li C = C anti- NH3(liq) / \ H CH3 trans-2-butene CH3CCCH3 H H H2, Pd-C C = C syn- Lindlar catalyst / \ CH3 CH3 cis-2-butene

Addition of X2 X X X | | | — C C— + X2  — C = C — + X2  — C — C — | | | X X X Br Br Br CH3CCH + Br2  CH3C=CH + Br2  CH3-C-CH Br Br Br

Addition of hydrogen halides: H H X | | | — C C— + HX  — C = C — + HX  — C — C — | | | X H X HX = HI, HBr, HCl Markovnikov orientation Cl CH3CCH + HCl  CH3C=CH2 + HCl  CH3CCH3 Cl Cl

Addition of water. Hydration. — C  C — + H2O, H+, HgO  — CH2 — C— H OH — C = C — “enol” keto-enol tautomerism Markovnikov orientation.

CH3CH2CCH + H2O, H2SO4, HgO  1-butyne O CH3CH2CCH3 2-butanone

As acids. terminal alkynes only! with active metals CH3CCH + Na  CH3CC-Na+ + ½ H2  with bases CH4 < NH3 < HCCH < ROH < H2O < HF CH3CCH + CH3MgBr  CH4 + CH3C CMgBr SA SB WA WB

Ag+ terminal alkynes only! CH3CH2CCH + AgNO3  CH3CH2CC-Ag+  CH3CCCH3 + AgNO3  NR (not terminal) formation of a precipitate is a test for terminal alkynes.

7. Oxidation CH3CH2CCCH3 + KMnO4  CH3CCH + hot KMnO4  CH3CCCH3 + O3; then Zn, H2O  CH3CH2COOH + HOOCCH3 CH3COOH + CO2 2 CH3COOH

Alicyclics nomenclature syntheses like alkanes, alkenes, alcohols, etc. reactions as expected exceptions: cyclopropane/cyclobutane

methylcyclopentane 1,1-dimethylcyclobutane trans-1,2-dibromocyclohexane

cyclopentene 3-methylcyclohexene 1,3-cyclobutadiene 4 2 5 1 6 cyclopentene 3-methylcyclohexene 1,3-cyclobutadiene

Cycloalkanes, syntheses A. Modification of a cyclic compound: H2, Ni Sn, HCl Mg; then H2O

Cycloalkanes, reactions: halogenation 2. combustion 3. cracking 4. exceptions Cl2, heat + HCl

exceptions: H2, Ni, 80o CH3CH2CH2-I CH3CH2CH3 Cl2, FeCl3 Cl-CH2CH2CH2-Cl H2O, H+ CH3CH2CH2-OH conc. H2SO4 CH3CH2CH2-OSO3H HI CH3CH2CH2-I

exceptions (cont.) + H2, Ni, 200o  CH3CH2CH2CH3

Cycloalkenes, syntheses KOH(alc) H+, Δ cyclohexene Zn

Cycloalkenes, reactions: addition of H2 8. hydroboration-oxid. addition of X2 9. addition of free radicals addition of HX 10. addition of carbenes addition of H2SO4 11. epoxidation addition of H2O,H+ 12. hydroxylation addition of X2 + H2O 13. allylic halogenation oxymerc-demerc. 14. ozonolysis 15. vigorous oxidation

H2, Pt Br2, CCl4 trans-1,2-dibromocyclohexane HBr H2SO4 Markovnikov H2O, H+ Br2 (aq.) dimerization

HF H2O,Hg(OAc)2 NaBH4 Markovnikov (BH3)2 H2O2, NaOH anti-Markovnikov HBr, perox. anti-Markovinikov polymer. CH2CO,hv PBA

trans-1,2-cyclohexanediol KMnO4 cis-1,2-cylohexanediol HCO3H trans-1,2-cyclohexanediol Br2, heat O3 Zn, H2O O=CHCH2CH2CH2CH2CH=O KMnO4, heat HO2CCH2CH2CH2CH2CO2H

Epoxides nomenclature syntheses 1. epoxidation of alkenes reactions 1. addition of acids 2. addition of bases

Epoxides, nomenclature ethylene oxide propylene oxide cyclopentene oxide (oxirane) (methyloxirane) Synthesis: C6H5CO3H cis-2-butene β-butylene oxide

acid catalyzed addition epoxides, reactions: acid catalyzed addition OH CH2CH2 H2O, H+ OH CH3CH2-O-CH2CH2 CH3CH2OH, H+ OH CH2CH2 Br HBr

2. Base catalyzed addition OH CH2CH2 CH3CH2-O-CH2CH2-OH H2N-CH2CH2-OH CH3CH2CH2CH2-OH

Mechanisms: Free radical substitution SN2 SN1 E2 E1 ionic electrophilic addition free radical electrophilic addition Memorize (all steps, curved arrow formalism, RDS) and know which reactions go by these mechanisms!

Free Radical Substitution Mechanism initiating step: X—X  2 X• propagating steps: 2) X• + R—H  H—X + R• R• + X—X  R—X + X• 2), 3), 2), 3)… terminating steps: 4) 2 X•  X—X 5) R• + X•  R—X 6) 2 R•  R—R

Substitution, nucleophilic, bimolecular (SN2) CH3 > 1o > 2o > 3o

Substitution, nucleophilic, unimolecular (SN1) 3o > 2o > 1o > CH3 1) 2)

Mechanism = elimination, bimolecular E2 3o > 2o > 1o

Elimination, unimolecular E1 3o > 2o > 1o

Free radical electrophilic addition of HBr: Initiating steps: 1) peroxide  2 radical• 2) radical• + HBr  radical:H + Br• (Br• electrophile) Propagating steps: 3) Br• + CH3CH=CH2  CH3CHCH2-Br (2o free radical) • 4) CH3CHCH2-Br + HBr  CH3CH2CH2-Br + Br• 3), 4), 3), 4)… Terminating steps: Br• + Br•  Br2 Etc.