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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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Prerequisites 333

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


Prerequisites 333

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.


Prerequisites 333

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


Prerequisites 333

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


Prerequisites 333

Structure

Carbonyl carbon: sp2 hybridized

Planar structure

Ch. 12 - 5


Prerequisites 333

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

Rxs of Carbonyl Compounds with Nucleophiles

One of the most important reactions:

nucleophilic addition to the carbonyl

recall:

Ch. 12 - 6


Prerequisites 333

Two important nucleophiles (bases):

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

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

Two important reactions:

Ch. 12 - 7


Prerequisites 333

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


Prerequisites 333

Alcohols by Reduction of Carbonyl Compounds

Ch. 12 - 17


Prerequisites 333

Alcohols by Reduction of Carbonyl Compounds

(1o alcohol)

Ch. 12 - 18


Hydrides

=

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


Prerequisites 333

Examples

skip ether ex

Ch. 12 - 23


Prerequisites 333

(neutralize)

Mechanism

Ch. 12 - 21


Prerequisites 333

Mechanism

Esters (carboxylic acids) are reduced to 1o alcohols

Ch. 12 - 22


3c summary of lialh 4 and nabh 4 reactivity

3C.Summary of LiAlH4 and NaBH4 Reactivity

reduced by LiAlH4

reduced by NaBH4

ease of reduction

Ch. 12 - 24


Prerequisites 333

Oxidation of Alcohols

special

CrO3

reagents

stronger

oxidants

Oxidation of Primary (1o) Alcohols

Ch. 12 - 25


Prerequisites 333

Special CrO3 reagent = PCC Reagent

pyridinium chlorochromate

Ch. 12 - 26


Prerequisites 333

3o

2o

PCC oxidation

1o

No Reaction

Ch. 12 - 27


Oxidation of 1 o alcohols to carboxylic acids

Jones reagent

Oxidation of 1o Alcohols to Carboxylic Acids

Ch. 12 - 28


Prerequisites 333

Oxidation: CrO3 + H2SO4[or H2CrO4 ]

[or KMnO4/HO(-)/Δ then H+/H2O]

Ch. 12 - 29


Prerequisites 333

Organometallic Compounds

organometallic compounds contain carbon-metal bonds

Ch. 12 - 34


Prerequisites 333

Preparation of Organolithium &Organomagnesium Compounds

Order of reactivity of RX

RI > RBr > RCl

Ch. 12 - 35


Prerequisites 333

Examples

Ch. 12 - 36


Prerequisites 333

Rxs with Compounds Containing Acidic Hydrogens

Grignard reagents and organolithium compounds are very strong bases

Ch. 12 - 37


Prerequisites 333

+ Mg2++ Br−

Examples as base

Ch. 12 - 38


Prerequisites 333

As nucleophiles:


Prerequisites 333

React as nucleophiles with epoxides

Ch. 12 - 39


Rxs of grignard organolithium reagents with carbonyls

Rxs of Grignard & Organolithium Reagentswith Carbonyls

Ch. 12 - 41


Prerequisites 333

examples

Ch. 12 - 44


Prerequisites 333

Reaction with esters

3o alcohol

Ch. 12 - 45


Prerequisites 333

Mechanism

Ch. 12 - 46


Prerequisites 333

Addition-Elimination

Ch. 12 - 49


Planning a grignard or rli synthesis

Planning a Grignard [or RLi ] Synthesis

Synthesis of

Ch. 12 - 50


Prerequisites 333

Method 1

Retrosynthetic analysis

Synthesis

Ch. 12 - 51


Prerequisites 333

Method 2

Retrosynthetic analysis

Synthesis

Ch. 12 - 52


Prerequisites 333

Method 3

Retrosynthetic analysis

Synthesis

Ch. 12 - 53


Prerequisites 333

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

Sodium or Lithium Alkynides (acetylides)

Preparation of lithium alkynides

Reaction with aldehydes or ketones

Ch. 12 - 58


Prerequisites 333

Synthesis and Protecting Groups

Ch. 12 - 59


Prerequisites 333

disconnection

Retrosynthetic analysis

However

Ch. 12 - 60


Prerequisites 333

Need to “protect” the –OH group first

Ch. 12 - 61


Prerequisites 333

Synthesis

Ch. 12 - 62


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