5. Alcohols

Question 1

Alcohols = water soluble, but if the alcohol has a long alkane chain, will it dissolve in water? How does a longer chain affect boiling point?

Answer 1

No. Higher boiling pt; alcs have higher boiling pts than alkanes in general b/c it has more H bonds (so more hydroxyl groups means raising bpt)

Question 2

How to convert ald/ket into primary/secondary alc w/ NaBH4

Answer 2

1) an H from BH4- attacks carbonyl C
2) carbonyl O and new H = single bond w/ carbonyl C
3) H2O or any H+ gets attacked by single carbonyl O

Question 3

Primary alc vs secondary alc

Answer 3

C-OH is bonded to 1 other C vs C-OH is bonded to 2 other Cs

Question 4

What can NaBH4 and LAH reduce?

Answer 4

LAH can reduce all CA, esters (into ald and primary alc), ald and ket; NaBH4 ONLY reduces ald/ket

Question 5

What type of rxn is going from alc to carbonyl compounds? What about from carbonyl compounds to alcs?

Answer 5

oxidation/[O]; reduction/[H]

Question 6

How to convert CA and esters into alc with LAH

Answer 6

1) LAH attacks carbonyl C –> single bonds around carbonyl C
2) single carbonyl O becomes a double bond again with carbonyl C and kicks out -OR –> ald
3) more LAH attacks like BH4 –> alc product

Question 7

ortho vs meta vs para

Answer 7

2 groups on adjacent C of phenols vs 2 groups = separated by a C of phenols vs 2 groups = opposite end of phenol ring

Question 8

How to name straight chain alcohols and aromatic alcohols?

Answer 8

alkyl alcohol and phenol

Question 9

PCC can oxidize/[O] primary alc to ald. But can PCC [O] ald to CA? Can PCC [O] secondary alc to ket?

Answer 9

No, you need H2O to [O] ald to CA and PCC doesn’t react w/ H2O –> using PCC stops at ald stage. PCC can [O] sec alc to ket

Question 10

Can tertiary alc be [O]?

Answer 10

Nope, they’re as oxidized as they can be w/o breaking C-C bonds; there is no H attached to the carbon w/ hydroxyl group (ie. Alpha H)

Question 11

What do you get when you [O] phenols vs quinones?

Answer 11

quinones vs hydroxyquinones

Question 12

What are common names of vit K1 and vit K2?

Answer 12

phylloquinone and menaquinone respectively

Question 13

Hydroquinone vs hydroxyquinone

Answer 13

benzene ring w/ 2 opposite -OH vs almost benzene ring w/ 2 opposite carbonyls and various number of -OH

Question 14

What’s ubiquinone?

Answer 14

aka Coenzyme Q in ETC; can be reduced to ubiquinol. It’s a small, hydrophobic molec that can move freely in inner mito membrane

Question 15

A dialcohol can react w/ ald/ket to form what? What about reverse?

Answer 15

acetal (primary C with 2 -OR groups => basically 2 ether groups on primary C)/ketal (secondary C with 2 -OR groups => basically 2 ether groups on secondary C). Acetals/ketals can serve as protecting groups for alcs b/c they don’t react with reducing agents

Acetals/Ketals can be reverted back into ald/ket + diols by reacting with aq acid + heat => deprotection

Question 16

How to form tosylate? What about reverse?

Answer 16

1) R-OH attacks electrophilic S of tosyl chloride –> Cl = leaving group
2) Pyridine acts as base and grabs H from R-OH-tosyl –> R-O-STosyl => tosylate

Tosylate acts as protecting group for alcs; can be reverted back to alcs by using a strong acid

Question 17

How to form mesylate? What about reverse?

Answer 17

1) triethylamine acts as base and grabs a methyl H from mesyl chloride –> nucleophilic methyl C
2) double bond forms b/w methyl C and S –> Cl = leaving group
3) R-OH attacks electrophilic S of mesyl –> methyl C = nucleophilic again
4) Methyl C grabs H from R-OH-mesyl –> R-O-mesyl => mesylate

Mesylate acts as protecting group for alcs; can be reverted back to alcs by using a strong acid

Question 18

Jones reagent (CrO3 with dilute sulfuric acid), salt dichromate (_Cr2O7), chromium, and KMnO4 can convert primary and secondary alcs to what?

Answer 18

Primary to CA, secondary to ket

Question 19

Geminal vs vicinal diols

Answer 19

Aka hydrates, Diols with -OH’s on same carbon vs aka GLYCOLS, Diols with -OH’s on adjacent carbons

Question 20

Diols are common protecting groups for which functional groups?

Answer 20

Ald and ket carbonyls

Question 21

How do you know if a reagent will [O] -OH to ald/ket or CA intentionally?

Answer 21

If they really only want ald/ket, they will use a reagent specific for [O] to ald/ket. Otherwise, it’ll go straight to CA

Question 22

How acidic are hydroxyl H’s?

Answer 22

Weakly acidic, but phenol H’s = more acidic than those of other alcs —> phenols can form salts w/ inorganic bases like NaOH. Phenols have high Ka/low pKa

Descending acidity: phenols > alkyl alcs > cyclo alcs (cyclo alcs rather donate e- instead of accepting them)

Question 23

Order of increasing bpt b/w alcs, alkanes and ald/ket

Answer 23

Alkanes < ald/ket < alcs

Question 24

Can NaBH4 reduce CAs?

Answer 24

Nope, not even to ald

Question 25

Esterification vs glycoside formation

Answer 25

When hydroxyl group of carb reacts with CA or CA derivative to make ester vs when hemiacetal reacts with alcs to make acetal aka glycoside