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Durham University

Department of Chemistry

Publication details for Dr David R.W. Hodgson

Rozatian, Neshat, Beeby, Andrew, Ashworth, Ian W., Sandford, Graham & Hodgson, David R. W. (2019). Enolization rates control mono- versus di-fluorination of 1,3-dicarbonyl derivatives. Chemical Science 10(44): 10318-10330.

Author(s) from Durham

Abstract

Fluorine-containing 1,3-dicarbonyl derivatives are essential building blocks for drug discovery and manufacture. To understand the factors that determine selectivity between mono- and di-fluorination of 1,3-dicarbonyls systems, we have performed kinetic studies of keto-enol tautomerism and fluorination processes. Photoketonization of 1,3-diaryl-1,3-dicarbonyl derivatives and their 2-fluoro analogues is coupled with relaxation kinetics to determine enolization rates. Reaction additives such as water accelerate enolization processes, especially of 2-fluoro-1,3-dicarbonyl systems. Kinetic studies of enol fluorination with Selectfluor™ and NFSI reveal the quantitative effects of 2-fluorination upon enol nucleophilicity towards reagents of markedly different electrophilicity. Our findings have important implications for the synthesis of α,α-difluoroketonic compounds, providing valuable quantitative information to aid in the design of fluorination and difluorination reactions.