Claisen rearrangement biological example

Besides the obvious biological interest, chorismate mutase is important for being a rare example of an enzyme that catalyses a pericyclic reaction (the Claisen rearrangement), which also occurs in solution without the enzyme, providing a unique... 

Claisen rearrangement plays an important part in the biosynthesis of several natural products. For example, the chorismate ion is rearranged to the prephenate ion by the Claisen rearrangement, which is catalysed by the enzyme chorismate mutase. This prephenate ion is a key intermediate in the shikimic acid pathway for the biosynthesis of phenylalanine, tyrosine and many other biologically important natural products. 

FIGURE 22-19 Biosynthesis of phenylalanine and tyrosine from chorismate in bacteria and plants. Conversion of chorismate to prephenate is a rare biological example of a Claisen rearrangement. 

The conversion of chorismate into prephenate is an example of a biologically relevant Claisen rearrangement. It is the key intermediate in the biosynthesis of aromatic amino acids (tyrosine, phenylalanine, and tryptophan) in bacteria, fungi, and higher plants (Figure 1.23) [23]. 

Claisen rearrangements are uncommon in biological pathways, but a well-studied example does occur during biosynthesis of the amino acids phenylalanine and tyrosine. Both phenylalanine and tyrosine arise from a precursor... 

Chapter 18—Ethers and Epoxides Thiols and Sulfides. Coverage of the Claisen rearrangement has been expanded, and a biological example of the reaction has been added in Section 18.4. Epoxide opening by amine nucleophiles has been added to Section 18.6. 

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