Masked omega-lithio ester enolates: synthetic applications
Miguel Yus1, Rosario Torregrosa, Isidro M Pastor
1Departamento de Química Orgánica, Facultad de Ciencias and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain. yus@ua.es
Molecules (Basel, Switzerland)
|November 17, 2007
Summary
This study introduces a new lithiation protocol using lithium and a catalytic amount of 4,4'-di-tert-butylbiphenyl (DTBB) for synthesizing functionalized esters and lactones from ortho esters.
Area of Science:
- Organic Chemistry
- Synthetic Methodology
Background:
- Ortho esters are versatile synthetic intermediates.
- Efficient methods for functionalizing ortho esters are valuable in organic synthesis.
Purpose of the Study:
- To develop a novel catalytic lithiation protocol for ortho esters.
- To explore the synthesis of functionalized esters and lactones using this method.
Main Methods:
- Lithiation of omega-chloro ortho esters using lithium and catalytic DTBB under Barbier-type conditions.
- Subsequent acid-catalyzed methanolysis or deprotection and acid treatment to yield esters and lactones.
Main Results:
- The protocol successfully synthesized functionalized esters (8, 9) and delta-lactones (11) from omega-chloro ortho esters.
- The method was also effective for bicyclic ortho esters, yielding gamma-lactones (15) and esters (8).
Conclusions:
- A practical and efficient catalytic lithiation protocol for ortho ester functionalization has been established.
- This method provides access to valuable ester and lactone derivatives.
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