Definitions [1]
Nomenclature is the system of assignment of names to organic compounds.
Key Points
- The IUPAC system provides a unique, systematic way to name carbon compounds based on structure, replacing confusing common names.
- An IUPAC name has three parts: prefix, parent, and suffix, reflecting the carbon chain and functional group.
- The parent name is based on the longest carbon chain, and its ending changes to –ane, –ene, or –yne depending on the number of bonds.
- Functional groups are shown as prefixes or suffixes, and the chain is numbered to give them the lowest possible number.
- If the suffix begins with a vowel, the final ‘e’ in the parent alkane name is dropped (e.g., propane → propanone).
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Williamson Synthesis (most important): R–O–Na + X–R' → R–O–R' + NaX. Primary alkyl halide is preferred (SN2 mechanism; 2° or 3° alkyl halide gives elimination).
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Acid-catalysed dehydration of alcohols:
\[\ce{2R - OH ->[H2SO4, 413K] R - O - R + H2O}\]
(works best for symmetrical ethers)
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From alcohols by catalytic dehydration:
\[\ce{2C2H5OH ->[Al2O3, 513-523K] C2H5 - O - C2H5 + H2O}\]
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Alkoxy mercuration-demercuration: \[\begin{array}{cc}
\phantom{}\ce{CH3 - CH = CH2 + C2H5OH + Hg(OCOCF3)2 -> CH3 - CH - CH2 - HgOCOCF3 ->[NaBH4/OH^{-}] CH3 - CH - CH3}\\
\phantom{................................................................................}|\phantom{.....................................................................}|\phantom{.}\\
\phantom{............................................................................................}\ce{OC2H5}\phantom{...........................................................}\ce{O-C2H5}\phantom{.}
\end{array}\]
