Birch reduction and Oppenauer oxidation.

Presented by :- PRADEEP JAISWALM.SC. PART-1 (2015-2016)SEM.-1ROLL NO. 6

CONTENTS :

• Reduction. Birch Reduction. Mechanism. Application . Oxidation.• Oppenauer Oxidation General reaction. Mechanism. Application.• References.

Reduction :-

Addition of hydrogen or removal of oxygen is called as reduction.

In this the addition of electropositive element takesplase.

It may also be defined as the process in which an atom or group of atoms taking part in a chemical reaction’ gain one or more electrons.

Birch reduction :- Principle:- Reduction of aromatic rings by means of alkali metals (Li or Na ) in liquid ammonia or amines with ethanol as proton donar,to give mainaly unconjugated dihydroderivatives is known as birch reduction.

General reaction:-

Mechanism:-

Li/ Et2 NH ,Me2NH

iLi ,NH3

(COOH)2 , H2O ‘ t- Bu OH.

APPLICATIONS :

Oxidation :- Addition of oxygen or removal of hydrogen is

called as oxidation.

In this the addition of electronegative element takes place.

It may be also defined as the process in which an atom or group of atoms, taking part in a chemical reaction, loses one or more electrons.

Oppenauer oxidation :- Principle:- The oxidation of alcohol to ketone in the

presence of aluminum tertiary butaoxide in benzene or acetone solution is called oppenaur oxidation.

The acetone acts as hydrogen acceptor and is converted in to isopropyl alcohol.

The presence of excess of acetone drives the reaction towards the oxidation product.

General reaction:-

Mechanism :-

Application :-•The oppenauer oxidation method is selective as carbon – carbon double bond is not attacked.

•The β and γ double bond generally migrate in to conjugation with the carbonyl group under the reaction condition.

•Oxidation of formates to carbonates they lose co2 to give alcohol which is further oxidized in to a ketone.

Reference :-Organic Reaction and Mechanism. ( P .S . Kalsi ).

March’s Advanced organic chemistry . ( Jerry march, Wiley.)

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