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foreversmilinganu

tischenko reaction mechanism,,, can ne one explain plzzz

waterdemon

Tischenko Reaction:

This reaction is modified cannizaro reaction.In this reaction
aldehyde having

-Hydrogen also undergo disproportionation
reaction using aluminium ethoxide at the place of sodium -
Hydroxide or potassium Hydroxide.

2CH₃-CH=O + Al(OC₂H₅)₃

CH₃-COOH + CH₃-CH₂-OH
(Acetaldehyde)

2CH₂=CH-CH=O + Al(OC₂H₅)₃

CH₂=CH-COOH

2-Methylpropanal inspite of having

-Hydrogen atom does
not undergo aldol condensation but gives cannizaro product
because

-Hydrogen atom is least acidic in nature.

Hope it is useful.
Cheers !!!!!!!!!!!!!!!!!

madmax

I don't know why but this reaction is one of my favourite

It enables aldehydes with or without alfa H to undergo cannizarro's reacn

Only disadvantage is produsts are not seperately obtained but combine to form ester

We use Al alkoxide and not of other metals like Na or Mg because they may give rise to an aldol product as well (when alfa H is present of course)

Here's the mechanism
The important step (worth remembering) is the hydride ion transfer ...Also seen in MPV reduction

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