Camphor from a-pinene

Oxidation of camphor with nitric acid opens the six-membered ring, affording cis-and irarw-camphoric acid. Sulfonation of camphor with concentrated sulfuric acid and acetic anhydride selectively yields 10-camphorsulfonic acid. 

Several syntheses of chiral camphor derivatives make use of the CH acidity of the methylene group attached in a-position to the carbonyl function (C-3). Thus, isoamyl nitrite converts camphor to 3-isonitrosocamphor which readily undergoes hydrolysis to the yellow camphorquinone. Bromination leads to 3-bromocamphor which is sulfonated to 3-bromocamphor-3-sulfonic acid with concentrated sulfuric acid. 3-Lithiated camphor obtained with phenyllithium is carboxylated to endo- and exo-isomers of camphor carboxylic acid. The Claisen condensation of camphor with esters of carboxylic acids provides enolized chiral 1,3-diketones, converting metal cations to chiral metal chelates. 

The enantiomers of camphorcarboxylic and sulfonic acids are used for resolution of enantiomers from racemic chiral amines and alcohols via diastereomeric salts and esters, respectively. Europium(III)- and praseodymium(III)-chelates of hydroxy-methylenecamphor derivatives are suitable chiral shift reagents for the determination of enantiomeric purity by integration of NMR spectra, because they exchange ligands with enantiomeric substrates such as alcohols and amines, thus forming diastereomeric chelates characterized by different spectra. 

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Carbocation rearrangements synthesis of camphor from a-pinene... 

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