Retro diels alder reaction and ortho effect

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

1. Retro diels alder reaction and 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   Fo rmation 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

11. THANK YOU