Phosphorylation Organocatalysts Highly Active by Design.

Area of Science:

• Organic Chemistry
• Catalysis
• Organometallic Chemistry

Background:

• Nucleophilic organocatalysts are crucial for phosphorylation reactions.
• Enhancing catalyst activity is key for efficient chemical synthesis.
• Imidazole and aminopyridine scaffolds are common in organocatalysis.

Purpose of the Study:

• To develop novel nucleophilic organocatalysts with improved activity for alcohol/phenol phosphorylation.
• To investigate the structural modifications that enhance catalytic performance.
• To elucidate the mechanism behind the observed activity enhancement.

Main Methods:

• Synthesis of imidazole- and aminopyridine-based organocatalysts featuring oligoether appendages.
• Evaluation of catalytic activity in alcohol/phenol phosphorylation reactions using various substrates.
• Computational studies using Density Functional Theory (DFT) to understand reaction mechanisms.
• Analysis of structure-activity relationships through the study of modified analogues.

Main Results:

• Organocatalysts with oligoether appendages demonstrated substantially enhanced activity compared to known benchmark catalysts.
• The attachment of oligoether chains to benzyl substituents on the active units significantly improved phosphorylation efficiency.
• DFT calculations and analogue studies supported the hypothesis of stabilizing n-cation interactions involving ethereal oxygens and the aza-heterocycle.

Conclusions:

• Oligoether appendages are effective in enhancing the activity of nucleophilic organocatalysts for alcohol/phenol phosphorylation.
• Stabilizing n-cation interactions are proposed as the key mechanism for the improved catalytic performance.
• The developed catalysts represent a significant advancement over existing benchmark catalysts for these transformations.