Chiral trialkanolamine-based hemicryptophanes: synthesis and oxovanadium complex

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Stereochemistry

Background:

• Development of novel chiral host molecules is crucial for molecular recognition and asymmetric synthesis.
• Hemicryptophanes represent a unique class of host molecules with potential applications in various chemical processes.

Purpose of the Study:

• To synthesize and characterize a novel class of chiral hemicryptophane hosts in diastereoisomerically pure forms.
• To determine the absolute configurations of the synthesized stereoisomers.
• To explore the complexation ability of the synthesized hosts.

Main Methods:

• Synthesis of a C3-symmetrical precursor using chiral pool reactants (R)- or (S)-glycidyl nosylate.
• Cyclotrimerization of the precursor in the presence of Scandium(III) triflate (Sc(OTf)3).
• Full characterization of the four stereoisomers, including circular dichroism (CD) spectroscopy for absolute configuration determination.

Main Results:

• Successful synthesis of two pairs of enantiomeric chiral hemicryptophanes (M-(R,R,R)-1a/P-(S,S,S)-1a and M-(S,S,S)-1b/P-(R,R,R)-1b) in diastereoisomerically pure forms.
• Distinct pairs of mirror-image CD spectra were obtained, confirming the enantiomeric relationship and enabling absolute configuration assignment.
• The formation of an oxovanadium(V) complex with hemicryptophane 1a was achieved and reported.

Conclusions:

• A novel class of chiral hemicryptophane hosts has been successfully synthesized with defined stereochemistry.
• CD spectroscopy proved effective for determining the absolute configurations of these complex chiral molecules.
• The synthesized hemicryptophanes demonstrate potential for complexation, as evidenced by the formation of an oxovanadium(V) complex.