DFT Calculations Rationalize Unconventional Regioselectivity in PdII-Catalyzed Defluorinative Alkylation of
Aili Feng1, Yiying Yang1, Chengbu Liu1
1Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China.
Abstract:
Density functional theory (DFT) calculations have been conducted to gain insight into the unique formation of the branched alkylation product in the PdII-catalyzed defluorinative alkylation of gem-difluorocyclopropanes with hydrazones. The reaction is established to occur in sequence through oxidative addition, β-F elimination, η1-η3 isomerization, transmetalation, η3-η1 isomerization, 3,3'-reductive elimination, deprotonation/N2 extrusion, and proton abstraction. The rate-determining step of the reaction is identified as the β-F elimination, featuring an energy barrier of 28.6 kcal/mol. The 3,3'-reductive elimination transition states are the regioselectivity-determining transition states. The favorable noncovalent π-π interaction between the naphthyl group of gem-difluorocyclopropane and the phenyl group of hydrazone is found to be mainly responsible for the observed regioselectivity.
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