This document discusses the McLafferty rearrangement, which is a reaction observed using mass spectrometry. It involves the cleavage of multiple bonds including the α and β positions of carbonyl compounds containing a γ-hydrogen. This rearrangement reaction was first observed by American chemist Fred McLafferty and involves the carbonyl group pulling off the γ-proton, splitting the molecule into an enol radical cation and a neutral alkene fragment. The document provides details on the mechanism of the rearrangement and its applications in molecular weight determination, element analysis, and structural elucidation using mass spectroscopy.

1. PREPARED BY
SUNNY MAURYA
M. PHARM SECOND SEMESTER
(PHARMACEUTICAL CHEMISTRY)
ADVANCED SPECTRAL ANALYSIS
SCHOOL OF PHARMACEUTICAL SCIENCES
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2. Contents
 MC LAFFERTY REARRANGEMENT
 INTRODUCTION
 GAMMA HYDROGEN
 REARRANGEMENT
 MECHANISM
 APPLICATION
 REFERENCES
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3. Mc lafferty rearrangement
 Fred Warren McLafferty was an American chemist
known for his work in mass spectrometry.
 He is best known for the McLafferty rearrangement
reaction that was observed with mass spectrometry.
 Mass spectroscopy is a technique used to determine the
mass of a given molecule.
 The molecule is placed inside the spectrometer and
ionized by high-energy electrons.
 After the molecules are ionized, they become radical
cations that can then be sorted and weighed.
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4. Mc lafferty rearrangement
 When hydrogen is available at the -position on carbonyl
compounds, these compounds go through a specific
rearrangement due to the cleavage of multiple bonds,
including the bonds at  and  -positions.
 This reaction is known as the McLafferty rearrangement.
 The rearrangement involves a six-membered ring
transition state in which the carbonyl group pulls off the
-proton, splitting the molecule into two pieces.
 These pieces consist of an enol radical cation and a
neutral alkene fragment.
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5. -hydrogen should contain
 Aldehyde
 Ketone
 Ester
 Carboxylic acid
 amides
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6. Rearrangement in carbonyl compound
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7. Mechanism of rearrangement
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8. Mechanism of rearrangement
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9. Rearrangement in ketone & carboxylic acid
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10. Application
 Molecular weight determination
 Element analysis
 Structural elucidation using mass specroscopy
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11. References
 https://www.slideshare.net/Justsci/mclafferty-
rearrangementpptx
 https://www.slideshare.net/darshanNU/mclaffertey-
rearrangement
 https://www.slideshare.net/MahendraMahi28/mc-
lafferty-rearrangement
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12. Thank you
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