Desymmetrization of Diols by Phosphorylation with a Titanium-BINOLate Catalyst

Area of Science:

• Organic Chemistry
• Catalysis
• Asymmetric Synthesis

Background:

• Chiral diols are important building blocks in organic synthesis.
• Developing efficient methods for their enantioselective functionalization is crucial.

Purpose of the Study:

• To desymmetrize prochiral diols via enantioselective phosphorylation.
• To investigate the catalytic system for optimal yield and enantioselectivity.

Main Methods:

• Utilized a titanium-BINOLate complex for phosphoryl transfer reactions.
• Evaluated various reaction parameters including chiral ligand, base, solvent, and stoichiometry.
• Employed pyrophosphates as phosphorylating agents.

Main Results:

• Achieved phosphorylation of nine 1,3-propane diols in 50-98% yield.
• Obtained high enantiomeric ratios up to 92:8 for specific diols.
• Identified an oligomeric chiral ligand species as the active catalyst.

Conclusions:

• The developed method offers a user-friendly approach for enantioselective phosphorylation.
• The method is effective for diols with protected amine groups.
• The findings support a catalytic mechanism involving an oligomeric species.