Synthesis of highly substituted cryptophane derivatives

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry

Background:

• Cryptophanes are molecular cages with diverse applications.
• Previous cryptophane derivatives were limited in substituent complexity.

Purpose of the Study:

• To synthesize novel cryptophane derivatives with a high degree of methoxy substitution.
• To explore new synthetic routes for complex cryptophane structures.

Main Methods:

• Synthesis of a novel cyclotrisyringyl derivative using scandium triflate (Sc(OTf)3).
• Characterization of cyclotrisyringyl and cyclotetrasyringyl derivatives via NMR, IR, and X-ray crystallography.
• Preparation and characterization of new highly substituted cryptophane derivatives (1-4).

Main Results:

• Successfully synthesized cryptophane derivatives 1-4 with nine and twelve methoxy substituents.
• Developed a new synthetic pathway involving a protected syringyl alcohol and Sc(OTf)3.
• Observed the formation of both anti- and syn-diastereomers, unlike cryptophane-A.
• Determined the stereochemistry of the new derivatives using X-ray crystallography.

Conclusions:

• The study presents the first cryptophane derivatives with over six substituents on the benzene rings.
• The developed synthetic method allows for the creation of highly functionalized cryptophane structures.
• The formation of diastereomers provides insights into the stereochemical control during synthesis.