Ppt is about NMR in that retro diels alder reaction and ortho effect.

1. Retro diels alder reactionand ortho effect
NAME: SIDDHESH RAJESH SUTAR
CLASS: MSC I
SEMESTER: II
UNIT: PAPER iii UNIT Iv
BATCH: ORGANIC CHEMISTRY
ROLL NO: 20
SUBJECT: organic CHEMISTRY
TOPIC: retro diels alder reaction and ortho effect

2. CONTENT
 Introduction to Mass Spectroscopy
 What is fragmentation ?
 What is retro diels alder reaction
 Properties of Retro-Diels alder reaction
 Ortho effect
 Reference

3. MASS SPECTROSCOPY
 Mass spectroscopy is the analytical
technique in which sample is converted to
rapidly moving cations by electrons
bombardment and separate the ions on the
basis of their mass to charge ratio.
 In general, the technique in which mass
spectrum measure the masses within the
sample

4. FRAGMENTATION

5. WHAT IS RETRO DIELS ALDER
REACTION
 The retro-Diels–Alder reaction (rDA) is the reverse of
the Diels–Alder reaction
 Formation of a diene and dienophile from a cyclohexene

6. MECHANISM OF RETRO-DIELS-ALDER
REACTION

7. PROPERTIES OF THE RETRO-DIELS-ALDER
REACTION
 Molecular ions containing a cyclohexene unit may fragment
to form conjugated di-olefinic (diene) and mono-olefinic
(ene) products.
 This fragmentation pathway was first recognized by
Biemann .
 The fragmentation can in principle proceed in a concerted
manner (a) or stepwise i.e. it can be regarded as a double D-
cleavage with the first being an allylic cleavage (b)

8. ORTHO ELIMINATION (ORTHOEFFECT)
Mass spectra of many 1,2-disubstituted aromatic compounds
are distinguishably different from those of
their meta or para isomers as the result of a phenomenon
known as the ortho effect.

9. ORTHO EFFECT REACTION

10. REFERENCE
 Mass spectroscopy by Jurgen H Gross
Pg no 276 and 304