1251069-80-3Relevant academic research and scientific papers
Lithiated fluorinated styrene oxides: Configurational stability, synthetic applications, and mechanistic insight
Capriati, Vito,Florio, Saverio,Perna, Filippo Maria,Salomone, Antonio
experimental part, p. 9778 - 9788 (2010/11/02)
The configurational stability of some lithiated fluorinated styrene oxides has been investigated. Chemical studies have shown that in ethereal solvents α-lithiated ortho-, meta-, and para-fluorostyrene oxides (2-Li, α-5-Li, and α-6-Li) are all configurationally stable in the reaction time scale, whereas a-lithiated ortho-, meta-, and paratrifluoromethylstyrene oxides (9-Li, 13-Li, and 14-Li) are configurationally unstable. Optically active oxiranyllithiums 2-Li and 9-Li, could be stereospecifically generated and quenched with electrophiles. The corresponding derivatives were then successfully subjected to regiospecific ring-opening reactions with amines to give fluorinated ssamino alcohols with a stereodefined quaternary carbinol center, which are useful synthons in medicinal chemistry. The barriers of inversion have been calculated (Eyring equation) for oxiranyllithiums 9-Li, 13-Li, and 14-Li by determining the enantiomeric ratios after electrophilic quenching on aging the enantioenriched organolithium for different times in THF; in the case of 9-Li, activation parameters have also been determined. Mechanisms that may be responsible of the racemization oxiranyllithiums 9-Li, 13-Li, and 14-Li undergo once generated are also discussed.
