Name reactions mechanism-Reimer tiemann reaction and Clemmensen reduction reaction

this involves reimer tiemann reaction and clemmensen reduction reaction. Reimer tiemann reaction is used for ortho-formylation of phenols when phenol reacts with chloroform and NaOH. While Clemmensen reduction reaction is used for reduction of carbonyl group into methylene group in the presence of zinc-amalgam and HCl

1. Name Reactions Mechanism 1. Reimer Tiemann Reaction 2. Clemmensen Reduction Reaction

2. Group # 10 Group Members

3. Reimer Tiemann Reaction

4. Reimer Teimann Reaction Definition The Reimer Tiemann reaction is a chemical reaction used for ortho-formylation of phenols; with the simplest example being the conversion of phenol to salicylaldehyde. The reaction was discovered by Karl Reimer and Ferdinand Tiemann.

5. Reimer Teimann Reaction Condition for Reimer Teimann Reaction P henols C 6 H 5 OH is treated with CHCl 3  (chloroform) in the presence of NaOH (sodium hydroxide) or KOH (potassium hydroxide). Intermediate Intermediate involved in Reimer Teimann reaction is carbene.

6. Reimer Teimann Reaction Chemical Reaction

7. Reimer Teimann Reaction Reaction Mechanism The chloroform is deprotonated by the strongly basic aqueous hydroxide solution, giving the chloroform carbanion. This chloroform carbanion readily undergoes alpha elimination, giving dichlorocarbene as the product . T he dichlorocarbene is the principle reactive species. The aqueous hydroxide also deprotonates the phenol reactant, yielding a negatively charged phenoxide. This negative charge is now delocalized into the benzene ring, causing it to be far more nucleophilic. This results in a nucleophilic attack on the dichlorocarbene, forming an intermediate dichloromethyl substituted phenol. This intermediate is subjected to basic hydrolysis to finally achieve the formation of the desired ortho-hydroxybenzaldehyde.

8. Reimer Teimann Reaction Mechanism

9. Reimer Teimann Reaction Example

10. Reimer Teimann Reaction Applications The Reimer Tiemann reaction is effective for ortho hydroxy-aromatic compounds, such as naphthol. Dichlorocarbene can react with alkenes and amines to respectively form dichlorocyclopropanes and isocyanides.

11. Clemmensen Reduction Reaction

12. Clemmensen Reduction reaction Definition It is a process of direct reduction of a carbonyl group to a methylene group. Clemmensen reduction is a chemical reaction described as a reduction of ketones (or aldehydes) to alkanes. This reaction is named after Erik Christian Clemmensen, a Danish chemist.

13. Clemmensen Reduction reaction Condition for Clemmesen Reduction Reaction It is done by using zinc amalgam and concentrated hydrochloric acid. The substrate must be tolerant of the strongly acidic conditions of the Clemmensen reduction (37% HCl). Intermediate In reaction mechanism of  Clemmensen reduction , the carbanion formed is the intermediate.

14. Clemmensen Reduction reaction Chemical Reaction For Aliphatic Carbonyl Compounds For Aromatic Carbonyl Compounds

15. Clemmensen Reduction reaction Mechanism of Reaction The mechanism for the Clemmensen reduction is not yet fully understood and there are two popular proposals. The "Carbanionic mechanism", where the zinc attacks the protonated carbonyl directly. The "Carbenoid mechanism", which is a radical process and the reduction happens on the surface of the zinc metal.

16. Clemmensen Reduction reaction

17. Clemmensen Reduction reaction Example

18. Clemmensen Reduction reaction Applications This reaction is widely used to convert carbonyl group into methylene group. It is used in the preparation of polycyclic aromatics and aromatics containing unbranched side hydrocarbon chains. To reduce aliphatic and mixed aliphatic - aromatic carbonyl compounds