Chemistry Reference
In-Depth Information
Figure 4.8
Molecular-orbital diagram for
electron transfer
In the case of a hydrocarbon, electron transfer
takes place from unsaturated bonds and
σ-bonds of strained compounds like
cyclopropane or ionic species. However,
ordinary saturated hydrocarbons rarely
undergo redox reactions. On the other hand,
even in the cases of saturated heteroatom
compounds containing heteroatoms like N, S
and O atoms, their oxidation is rather easy
since electron transfer from lone paired
electrons of a heteroatom readily takes place.
Furthermore, depending on the heteroatom (Z),
C-Z and Z-Z bonds can be reductively cleaved.
Isolated olefins are generally difficult to oxidize,
but olefins with a directly attached heteroatom,
for instance enamines, enol ethers and silyl enol
ethers (
Figure 4.9
), are electron-rich olefins,
therefore their oxidation potentials decrease
significantly and they are easily oxidized.
Moreover, heteroatoms greatly contribute to
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