A SEMIEMPIRICAL AND ABINITIO ANALYSIS OF FLUOROKETONES AS REACTIVE ELECTROPHILES

Fluoroketones have long been known as highly reactive, electrophilic carbonyl compounds and have become increasingly important as inhibitors of hydrolytic enzymes. The enhanced electrophilicity of fluoroketones relative to ketones has been presumed to be due to carbonyl polarization. Results of MNDO and 6-31G** calculations presented in this study argue against this explanation and provide a rationale based on the relative energy of the acceptor (LUMO) orbitals for fluoroketones and ketones. Fluoroketones acceptor orbital energy levels were found to be 21.2 to 28.4 kcal/mole lower than the analogous ketone.