Mechanisms

Question 1

Addition of hydrogen halides

Answer 1

Alkene–> Alkyl halide
Reagent= HX
Markovnicov
Rearrangements

Question 2

HBR/peroxides

Answer 2

Alkene–>Alkyl halide
Reagent= HX/peroxide
Anti-Matk

Question 3

Hydration of alkenes

Answer 3

Alkene–>alcohol
Reagent= H20, H+ or H3O+
Mark
Rearrangements

Question 4

Oxymercuration-demercuration

Answer 4

alkene–>alcohol
Reagents= 1)Hg(oAc)2, H2O
2)NaBh4
Mark

Question 5

Alkoxymercuration-demercuration

Answer 5

Alkene–>ether
Reagents= 1)Hg(OAc)2, ROH
2)NaBh4
Mark

Question 6

Hydroboration

Answer 6

Alkene–>alcohol
Reagents= 1)BH3*THF
2)H2O2, -OH
Anti-mark

Question 7

Addition of halogens to alkene

Answer 7

Alkene–>halide
Reagents= X2
Anti-addition

Question 8

Formation of halohydrin

Answer 8

Alkene–>halohydrin (alcohol and halide group)
Reagents= X2; H2O
Anti-addition
Nucleophile adds to the carbon with the most substituents.

Question 9

Hydrogenation

Answer 9

Alkene–>Alkane
Reagents= H2; Pd, Pt or Ni
Syn-addition

Question 10

Simmons-smith

Answer 10

Alkene–>cyclopropane

Reagents= ICH2ZNI or CH2,I2 and zn,CuCl

Question 11

Halogenated cylopropane

Answer 11

Alkene–>halogenated cyclopropane

Reagents= CX3; KOH; H2O

Question 12

Epoxidation of Alkene

Answer 12

Alkene–>Epoxide

Reagents= RCO3H; CCl4 or mCPBA

Question 13

Acid catalyzed ring opening of epoxides

Answer 13

Alkene–>glycol
Reagents= strong peroxides; HCO3H and H3O+ or CH3CO3H and H3O+
Anti-addition

Question 14

Syn dihydrogenation of alkenes

Answer 14

Alkene–>syn glycol
Reagents=KMnO4; OH (cold and dilute) or OsO4; H2O2
Syn addition

Question 15

Ozonolysis

Answer 15

Alkene–>ketone+Aldehyde
Reagents=1) O3 (-78 C)
2)(CH3)2S

Question 16

Oxidative cleavage of alkenes

Answer 16

Alkene–> Ketone +carboxylic acid

Reagents= KMnO4 (warm and Concentrated)

Question 17

Formation of an acetylide ion

Answer 17

Terminal Alkyne–>Acetylide ion

Reagents= NaNH2

Question 18

Formation of internal alkynes

Answer 18

acetylide ion-->Internal alkyne
Reagents=Unhindered alkyl halide (Primary or methyl) ex: CH3-I
Sn2 Reaction (nucleophile attacks carbon)

Question 19

E2 Alkyne Reaction

Answer 19

Acetylide ion-->Terminal alkyne + Alkene
Reagents= hindered alkyl halide (2 or 3) ex: (CH3)3-I
E2 reaction (base attacks hydrogen)

Question 20

Addition of carbonyl compounds

Answer 20

Acetylide ion + aldehyde or ketone–>Acetylenic Alcohol

Reagents=Aldehyde or ketone; and H3O+

Question 21

Synthesis of Alkynes

Answer 21

Alkane-->Vicinal/geminal dihalide-->Alkyne
Reagents= Strong Base
KOH @200C--> favors internal alkyne
NaNH2 @150C--> favors terminal alkyne
Elimination reaction

Question 22

Addition reaction

Answer 22

Alkyne–>alkane

Reagents= 2H2; Pd, Pt or Ni

Question 23

Hydrogenation with Lindlar’s catalyst

Answer 23

Alkene–>Cis alkene

Reagents= H2, Pd/BaSO4, quinoline,CH3OH

Question 24

Reductions of Alkynes with Metal Ammonia

Answer 24

Alkyne–>trans alkene
Reagents= Na/NH3
or NaNH3(l) (-78 C)
Anti-addition

Question 25

Addition of Halogen (alkyne)

Answer 25

Alkyne-->Vicinal dihalide-->Tetrahalide Reagents= 2 moles of X2 Vicinal dihalide is a mixture of cis/trans isomers

Question 26

Addition of Hx (alkyne)

Answer 26

Terminal Alkyne-->Geminal dihalide Reagent= 2HX (Cl, Br, I) Markovnicov

Question 27

Addition of HX and ROOR

Answer 27

Terminal Alkyne-->Bromoalkene Reagents=HX and ROOR Anti-mark

Question 28

Hydration of Alkynes

Answer 28

Alkyne-->enol-->ketone Reagents=HgSO4; H2SO4 Mark Keto-enol Tautomerization

Question 29

Hydroboration-Oxidation Reaction (alkyne)

Answer 29

Alkyne-->enol-->aldehyde Reagents= Sia2BH; H2O2; NaOH Anti-mark Keto-enol Tautomerization

Question 30

Oxidation of Alkynes

Answer 30

Alkyne-->dikeytone | Reagents= KMnO4, dilute, H2O, neutral

Question 31

Permanganate Oxidation of alkynes

Answer 31

Alkyne-->2 carboxylic acids Reagents= KMnO4, KOH, H2O, heat (basic) Cleavage of the triple bond

Question 32

Ozonolysis

Answer 32

Alkyne-->2 carboxylic acids Reagents= O3 (-78C); H2O Cleavage of triple bond