Friday, 15 August 2014

problem of oxymercurationdemercuration




Free radicals- Preparation from mercury hydrides        

alkynes some reaction mechanisms

Alkynes- addition of hydrogen halides        


Alkynes- hydration to ketones (Markovnikov)        


Alkynes- isomerisation        



Alkynes- reduction to E-alkene        


Alkynes- reduction to Z alkene        






alkene -reaction summary


Alkenes- addition of Br2        



Alkenes- anti-dihydroxylation        


Alkenes- CCl3 and NaOH with alkene (carbene formation).        



Alkenes- Diels Alder- cycloaddition        



Alkenes- Diols from OsO4 to aldehydes (IO4/H2O)        


Alkenes- electrophilic addition of Br2 and H2O        



Alkenes- electrophilic addition of H2O        



Alkenes- electrophilic addition of HBr        



Alkenes- electrophilic addition of HBr (Hydride Shift)        




Alkenes- formation by dehydrogenation of alcohols        



Alkenes- formation by elimination of charged leaving group (Hoffman product)        


Alkenes- formation by elimination of HHal from RHal (E2)        

Alkenes- free radical addition of HBr        



Alkenes- hydroboration        




Alkenes- organoboranes to alcohols        


Alkenes- I2 AgOAc, AcOH (dry)- Prevost reaction.        



Alkenes- I2 AgOAc, AcOH (wet)- Woodward reaction        




Alkenes- oxymercuration to form alcohol        




Alkenes- ozonolysis        



Alkenes- Ozonolysis of cyclohexene (1,6 dialdehyde)        


Alkenes- syn-dihydroxylation (OsO4)        




Wednesday, 13 August 2014



Favorskii Rearrangement

α -Haloketones with base afford enolates which rearrange to give esters via cyclopropanones.
Mechanism


                          Favorskii rearrangement mechanism



The direction of ring opening of cyclopropanone is determined by the more stable carbanion, formed in the reaction.
Examples: