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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. Assignments. Due the second recitation:

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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


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.


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


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

Synthesis

CHAPTER 12

Alcohols from Carbonyl Compounds Oxidation-Reduction

Organometallic Compounds

Srtucture of the carbonyl group

C=O addition/ROH oxidation

CHEM

334

Chapter 12


Structure

Carbonyl carbon: sp2 hybridized

Planar structure

Ch. 12 - 5


Structure of the Carbonyl Group, Carbonyl compounds

Others:

Y = OH, OR’, NH2, X, etc.

aldehyde

alkanal

ketone

alkanone

Ch. 12 - 4


Rxs of Carbonyl Compounds with Nucleophiles

One of the most important reactions:

nucleophilic addition to the carbonyl

recall:

Ch. 12 - 6


Two important nucleophiles (bases):

Hydrides (H:(-) from NaBH4 & LiAlH4 )

Carbanions (from R:(-)(+)Li & R:(-)(++)Mg(-)X )

Two important reactions:

Ch. 12 - 7


Oxidation-Reduction Rxs

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


Alcohols by Reduction of Carbonyl Compounds

Ch. 12 - 17


Alcohols by Reduction of Carbonyl Compounds

(1o alcohol)

Ch. 12 - 18


=

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


Examples

skip ether ex

Ch. 12 - 23


(neutralize)

Mechanism

Ch. 12 - 21


Mechanism

Esters (carboxylic acids) are reduced to 1o alcohols

Ch. 12 - 22


3C.Summary of LiAlH4 and NaBH4 Reactivity

reduced by LiAlH4

reduced by NaBH4

ease of reduction

Ch. 12 - 24


Oxidation of Alcohols

special

CrO3

reagents

stronger

oxidants

Oxidation of Primary (1o) Alcohols

Ch. 12 - 25


Special CrO3 reagent = PCC Reagent

pyridinium chlorochromate

Ch. 12 - 26


3o

2o

PCC oxidation

1o

No Reaction

Ch. 12 - 27


Jones reagent

Oxidation of 1o Alcohols to Carboxylic Acids

Ch. 12 - 28


Oxidation: CrO3 + H2SO4[or H2CrO4 ]

[or KMnO4/HO(-)/Δ then H+/H2O]

Ch. 12 - 29


Organometallic Compounds

organometallic compounds contain carbon-metal bonds

Ch. 12 - 34


Preparation of Organolithium &Organomagnesium Compounds

Order of reactivity of RX

RI > RBr > RCl

Ch. 12 - 35


Examples

Ch. 12 - 36


Rxs with Compounds Containing Acidic Hydrogens

Grignard reagents and organolithium compounds are very strong bases

Ch. 12 - 37


+ Mg2++ Br−

Examples as base

Ch. 12 - 38


As nucleophiles:


React as nucleophiles with epoxides

Ch. 12 - 39


Rxs of Grignard & Organolithium Reagentswith Carbonyls

Ch. 12 - 41


examples

Ch. 12 - 44


Reaction with esters

3o alcohol

Ch. 12 - 45


Mechanism

Ch. 12 - 46


Addition-Elimination

Ch. 12 - 49


Planning a Grignard [or RLi ] Synthesis

Synthesis of

Ch. 12 - 50


Method 1

Retrosynthetic analysis

Synthesis

Ch. 12 - 51


Method 2

Retrosynthetic analysis

Synthesis

Ch. 12 - 52


Method 3

Retrosynthetic analysis

Synthesis

Ch. 12 - 53


RMgX & RLi reagents cannot be prepared in the presence of the following groups because of reactions (acid-base or nucleophilic addition) :

Ch. 12 - 56


Sodium or Lithium Alkynides (acetylides)

Preparation of lithium alkynides

Reaction with aldehydes or ketones

Ch. 12 - 58


Synthesis and Protecting Groups

Ch. 12 - 59


disconnection

Retrosynthetic analysis

However

Ch. 12 - 60


Need to “protect” the –OH group first

Ch. 12 - 61


Synthesis

Ch. 12 - 62


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