Project Overview

1
www.chem.sc.edu/faculty/bryson/index.html
Linked to course syllabus and WEB PAGE
CHEM 334
Prerequisites 333
synthesis
29/32
Modified from sides of William Tam Phillis Chang
2
Assignments
Due the second recitation (1)
Answer the following question in some detail.
What study activity (activities) helped you the
most in CHEM 333?
(2) Complete review work sheet of 333
reactions.
3
SYLLABUS must read
(linked to the Home and WEB Page)
Text Solomons (10th ed) Schedule of tests and
projected pace Honor code Policy - grading
scale Recitation WEB PAGE Homework problems,
aids, etc
www.chem.sc.edu/faculty/bryson/index.html
4
Hydrogenation of double bonds olefins and
carbonyls LiAlH4 NaBH4 Oxidation w/ PCC Oxidation
w/ H2CrO4 and KMnO4 Organometallic compounds R-Li
RMgX Organometallics as bases Organometallics
as Nu(-) with carbonyls epoxides esters Synthesi
s
CHAPTER 12 Alcohols from Carbonyl
Compounds Oxidation-Reduction Organometallic
Compounds Srtucture of the carbonyl group CO
addition/ROH oxidation
CHEM 334
Chapter 12
5

• Structure

Carbonyl carbon sp2 hybridized Planar structure
Ch. 12 - 5
6
?
?
Ch. 12 - 4
7
Rxs of Carbonyl Compounds with Nucleophiles
One of the most important reactions
nucleophilic addition to the carbonyl
recall
Ch. 12 - 6
8
Two important nucleophiles (bases)
Hydrides (H(-) from NaBH4 LiAlH4 ) Carbanions
(from R(-)()Li R(-)()Mg(-)X )
Two important reactions
Ch. 12 - 7
9
reduction increase in hydrogen content or
decrease in oxygen content
oxygen content decreases
carboxylic acid
aldehyde
hydrogen content decreases
oxidation increase in oxygen content or decrease
in hydrogen content
Ch. 12 - 8
10
Ch. 12 - 17
11
Ch. 12 - 18
12
Hydrides
LAH
LiAlH4
Nucleophilic and very basic React violently
with H2O or protic sources Rxs in Et2O or THF,
reduces all carbonyl groups
less reactive less basic than LiAlH4 uses
protic solvent (e.g. EtOH) reduces only aldehydes
and ketones
NaBH4
Ch. 12 - 19
13
Examples
skip ether ex
Ch. 12 - 23
14
Mechanism
Ch. 12 - 21
15
Mechanism
Esters (carboxylic acids) are reduced to 1o
alcohols
Ch. 12 - 22
16
3C. Summary of LiAlH4 and NaBH4 Reactivity
reduced by LiAlH4
reduced by NaBH4
ease of reduction
Ch. 12 - 24
17
Oxidation of Primary (1o) Alcohols
Ch. 12 - 25
18
Special CrO3 reagent PCC Reagent
pyridinium chlorochromate
Ch. 12 - 26
19
PCC oxidation
1o
No Reaction
Ch. 12 - 27
20
Oxidation of 1o Alcohols to Carboxylic Acids
Ch. 12 - 28
21
Oxidation CrO3 H2SO4 or H2CrO4
or KMnO4/HO(-)/? then H/H2O
Ch. 12 - 29
22
organometallic compounds contain carbon-metal
bonds
Ch. 12 - 34
23
Order of reactivity of RX RI gt RBr gt RCl
Ch. 12 - 35
24
Examples
Ch. 12 - 36
25
Rxs with Compounds Containing Acidic Hydrogens
Grignard reagents and organolithium compounds are
very strong bases
Ch. 12 - 37
26
Examples as base
Ch. 12 - 38
27
As nucleophiles
28
React as nucleophiles with epoxides
Ch. 12 - 39
29
Rxs of Grignard Organolithium Reagentswith
Carbonyls
Ch. 12 - 41
30
examples
Ch. 12 - 44
31
Reaction with esters 3o alcohol
Ch. 12 - 45
32
Mechanism
Ch. 12 - 46
33
Addition-Elimination
Ch. 12 - 49
34
Planning a Grignard or RLi Synthesis
Synthesis of
Ch. 12 - 50
35
Method 1 Retrosynthetic analysis
Synthesis
Ch. 12 - 51
36
Method 2 Retrosynthetic analysis
Synthesis
Ch. 12 - 52
37
Method 3 Retrosynthetic analysis
Synthesis
Ch. 12 - 53
38
RMgX RLi reagents cannot be prepared in the
presence of the following groups because of
reactions (acid-base or nucleophilic addition)
Ch. 12 - 56
39
Sodium or Lithium Alkynides (acetylides)
Preparation of lithium alkynides
Reaction with aldehydes or ketones
Ch. 12 - 58
40
Ch. 12 - 59
41
Retrosynthetic analysis
However
Ch. 12 - 60
42
Need to protect the OH group first
Ch. 12 - 61
43
Synthesis
Ch. 12 - 62