This presentation includes photo-addition and photo-fragmentation reactions.

1. Photoaddition and Photo-
Fragmentation reaction
Submitted By:
AASHU VIJAY
AMITY INSTITUTE OF PHARMACY

2. PHOTOADDITION REACTION - Biomolecular photochemical process in which a single product is formed by
electronically excited molecules.
1. PATERNO BUCHI REACTION- Photoaddition of triplet carbonyl group with ground state of alkene
forming 4 membered oxetane.
1. ADDITION OF C-H ACROSS A C=O BOND 3. ADDITION OF X-H ACROSS C=C BOND
AMITY INSTITUTE OF PHARMACY
AMITY INSTITUTE OF PHARMACY

3. PHOTOFRAGMENTATION REACTION - The light-induced reactions of organic compounds for introduction of functional
groups at inactivated carbons through free radical additions are known as the photofragmentation reactions. This reaction provide
diradicals and zwitterionic intermediates like carbenes and nitrenes.
Alpha cleavage (sigma bond directly attached to the chromophore) is primary process- Homolytic fragmentation forms diradicals
followed by thermal process (loss of small molecule like CO,CO2,N2,O2 etc.
AMITY INSTITUTE OF PHARMACY
AMITY INSTITUTE OF PHARMACY
Beta cleavage is done
when there is leaving
group is attached
directly to alpha carbon.
It is type of beta
elimination.
Example:Barton reaction,
Hypohalite reaction and Hofmann
loffler freytag reaction

4. THANK YOU
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AMITY INSTITUTE OF PHARMACY