Alcohols CH 10/11

what are alcohols

organic compounds with hydroxyl group(s) -OH

R-OH

Alcohols with two hydroxyl groups are called

diols or glycols

ex ethane 1,2 diol or ethylene glycol

Physical properties of alcohols

• the boiling point increases with increasing molecular weight and decreases with increasing branching

• polar

• hydrogen bonding and dipole-dipole attractions

Solubility properties of alcohols

• alcs with 1-3 alkyl groups are miscible

• hydroxyl group is HYDROPHILIC

• alkyl group is HYDROPHOBIC

alkoxide ion

• strong nucleophiles

• strong bases

what is the pKa range of an alc

15.5 - 18

why is phenol more acidic than cyclohexanol

more stable, charge delocalized over oxygen and the 3 carbons

synthesis using sodium/potassium metal

R-O-H +Na → R-O Na+ + hydrogen gas

what is used when sodium/potassium metal doesn’t work

sodium hydride

Oxymercuration-demercuration (alkene into alc)

(1) Hg(OAc)2/ H2O
(2) NaBH4
-follows markovnikov's orientation
-H and -OH on products

Hydroboration-oxidation (alkene into alc)

REAGENTS:
(1) BH3/ THF
(2) H2O2/ NaOH
-follows anti-markovnikov's orientation
-H and -OH on products
-syn addition

What are Grignard reagents?

• R-Mg-X

• strong nucleophiles

• great to make new C-C bonds

• always carried out in DRY solvent

• incompatible w/ acidic protons (OH, NH, SH)

• R is either alkyl, vinyl, or aryl

• X is either I, Br, or Cl

organolithium comps

• strong nucleophiles

• R-Li

R-X + 2Li --> LiX + R-Li
REAGENTS:
2 Li/ether

thiols “mercaptans”

• sulfur analogs of alcohols

• R-SH

• lower pKa (=10)

• thiolates weaker bases than alkoxides

oxidation in ogro is the…

addition of o/o2, addition of x, or the loss of h2

reduction in orgo is the…

loss of o/o2/x or the addition of H- or h2

reagents that stop oxidation of primary alcohols

• NaClO (bleach)

• PCC

• DMP

• PDC

how does NaClO and tempo work

oxidizes primary alc into aldehydes at high yields and rates

which arent oxidized under normal circumstances

tertiary alcs, resistant to reagents

other oxidizing reagents

• KmnO4

• HNO3

• CuO

secondary alc are oxidized to….

ketones

primary alcs are oxidized to…. by …..reagents and oxidized to… by ….reagents

aldehydes by mild …. carboxylic acids by strong

what type of reaction

elimination

what type of reaction

oxidation

what reagent is used

T3Cl (makes tosylates)

what reagent is used

H+

what reagent is used

A base

what reagents are used

1. Hg(OAc)

2. H2O