Question

can't sleep gonna go through some chem notes

Answer 1

Alkene/Alcohol Rxn List:

1. acid-catalyzed hydration (H2SO4 + H2O)
> Markovnikov addition of -OH and H
> susceptible to rearrangements
2. oxymercuration demercuration (Hg(OAc)2 + H2O, then NaBH4 + OH-)
> Markovnikov addition of -OH and H
> not susceptible to rearrangements
3. hydroboration-oxidation (BH3 + THF, then H2O2 and NaOH)
> anti-Markovnikov addition of -OH and H
> syn addition
4. alkyl halide addition (HX + HOH)
> not preferred due to tendency to eliminate
> degree of substitution of the OH determines SN1 vs SN2
5. PBr3
> replaces -OH with -Br via SN2
6. SOCl2
> replaces -OH with -Cl via SN2 if pyridine is present; by itself will retain stereochemistry
7. Leaving groups
tosylate, mesylate, triflate (know these structures)
8. dehydration (H2SO4) to synthesize ethers
> not preferred due to tendency to eliminate
> acid will protonate the -OH turning it into a good LG, then another molecule of the alcohol attacks
9. williamson ether synthesis
R-ONa + ROH --> ROR
R-ONa dissociates into alkoxide, attacks the R as the Lg leaves (SN2)
10: alkoxymercuration-demercuration
almost the same as #2 except uses Hg(CF3CO2)2 and t-BuOH instead of water. adds TBuO to the double bond

Answer 2

Protecting groups:

> isobutylene + H2SO4, adds a t-butyl protecting group and replaces the H on -OH
can be removed w/ aqueous acid

> silyl ether
adds Me2Si-t-Butyl using imidazole and DMF; removed w/ Bu4N+F- and THF
*** professor prefers this one for some reason ***

Answer 3

Epoxidation and ring-opening:
Epoxidation: mCPBA (draw a benzene ring, put a Cl group and a COOOH group meta to each other. oxygen nearest to the H gets donated to the double bond in circular mechanism
Ring-opening: 2 methods
acid catalyzed: O attacks the H on the acid, creates good LG while water attacks the more hindered end (based on carbocation stability, almost like SN1)
base-catalyzed: base (often an alkoxide) attacks the less hindered end (almost like SN2)

Answer 4

pKas to know:
water is about 14
phenols are more acidic than regular alcohols (more s character and stabilization of resonance), about 10
ethanol is about 16 (which is why water can protonate the OH)
hydronium is like -1 or -2 ish
ammonia is the most basic, pka 36
ethyne is 25 (not the best acid, but much better than ethene or methane because of higher s character)

might not need to know these two but eh
diethylmalonate is about 13
acetone is about 19

Answer 5

Aromatics Review:
1. chlorination/bromination
add FeCl3/FeBr3 respectively + the appropriate diatomic halogen
2. nitration:
add HNO3 + H2SO4, to add NO2 to the ring
sulfuric acid activates the HNO3 making it a better electrophile
3. sulfonation
add H2SO4 and SO3 to add HSO3 to the ring
4. friedel crafts
> alkylation: AlCl3 + alkyl chloride. susceptible to rearrangements
> acylation: AlCl3 + acyl chloride, not susceptible to rearrangements. however, must remove the C=O bond w/ clemmenson reduction if the C=O bond is not desired
5. clemmenson reduction: adding Zn(Hg) + HCl reflux knocks off the C=O bond and replaces w/ the appropriate # of hydrogens
6. KMNO4 + OH- + H3O+ + heat, basically does the opposite of clemmenson, adds a C=O bond

Elimination mechanisms
1. EtONa/EtOH -> zaistev
2. bulky base -> hoffman

Answer 6

I really hope this isn't on the test but just in case: diazonium intermediate and its possible products

1. start w/ benzene
2. nitration
3. reduction to NH2 using SnCl2
4. conversion to diazonium using NaNO2 + HCl
5. 8 possible products via substituting diazonium with another compound

CuBr/CuCl/CuCN will replace with Br/Cl/CN respectively
HBF4 will replace w/ F
Cu2O Cu2+ will replace with OH
H3PO2 will replace with H
KI will replace with I