[sapta]

i am having a problem in the basic concept.According to one of my books the followings are  examples of MPV reduction-

1.  CH3.CO.CH3  +  cyclohexanol-------------->CH3.CHOH.CH3   +cyclohexanone.

2.CH3.CO.CH3 + CH3.CHOH.CH3 ----------->CH3.CHOH.CH3  +CH3.CO.CH3

the reagent is(of course) [(CH3)₂CHO]₃Al  in iso-propanol.


BUT THEN, WHAT'S THE DIFFERNCE WITH Oppnauer oxidation where sec. alcohols are oxidised to ketones at the expense of acetone(or any other ketone).The reagent is of course different but why is the former called a reduction reaction while the latter is an oxidation reaction?
--------------------------------------------------------------
OPPANAUER OXIDATION-

R₁CHOH.R₂  +R₃CO.R₄-------->R₁CO.R₂ + R₃CHOH.R₄.

REAGENT is [(CH₃)₃CO]₃Al.




 

[movies]

You are correct that the Meerwein-Ponndorf-Verley reduction and the Oppenauer oxidation are essentially the same reaction.  The key to the process is that the reaction is constantly in equilibrium; that is to say that the forward are reverse reaction are constantly going on.  The difference is what solvent you use.  For reduction, you use isopropanol and for oxidation you use acetone.  The idea is that you drive the equilibrium by adding a large amount of one of the materials involved in the equillibrium.  It's an elegant application of Le Chattlier's principle!

[sapta]

Very very thanks . It's clear to me now.