Isotopic Labeling Experiments Solve the Hedycaryol Problem

Area of Science:

• Natural Product Chemistry
• Organic Chemistry
• Biochemistry

Background:

• Hedycaryol is a sesquiterpene alcohol crucial for synthesizing eudesmols and guaiols.
• Complex conformational dynamics of hedycaryol hinder complete Nuclear Magnetic Resonance (NMR) assignment in mixtures.

Purpose of the Study:

• To overcome challenges in NMR assignment for hedycaryol.
• To access both hedycaryol enantiomers for detailed analysis.
• To investigate the stereochemical pathway of the Cope rearrangement.

Main Methods:

• Enzymatic synthesis of isotopically labeled hedycaryol using a mutated plant enzyme.
• Utilized a bacterial enzyme to obtain both hedycaryol enantiomers.
• Employed NMR spectroscopy to analyze the synthesized compounds.

Main Results:

• Successfully achieved full NMR assignment for hedycaryol.
• Provided access to both enantiomers of hedycaryol through enzymatic synthesis.
• Elucidated the stereochemical course of the Cope rearrangement of hedycaryol.

Conclusions:

• Enzymatic synthesis is a viable strategy for overcoming NMR assignment difficulties in complex natural products.
• The study provides a foundation for understanding sesquiterpene biosynthesis and rearrangements.
• This work enables further investigation into the chemistry of eudesmols and guaiols.