Enantioselective Synthesis of Planar Chiral Ferrocene Triflones
Résumé
A multi-gram scale synthesis of ferrocenetriflone was optimised from
ferrocenesulfonyl fluoride and Me3SiCF3 (Ruppert reagent).
Enantioselective deprotolithiations were then optimised using
alkyllithiums in the presence of catalytic (+)-sparteine to afford 2-
substituted ferrocene triflones in 79-84% ee. The use of chiral lithium
amides in the presence of in situ traps was also optimised and was
found to outperform alkyllithium∙chiral diamine chelates for the first
time in the ferrocene series, with 89-93% ee. Crystallisation of
derivatives afforded enantiopure compounds that were engaged in
deprotolithiation-electrophilic trapping sequences, a halogen ‘dance'
reaction and transition metal-promoted coupling to afford a wide range
of variously polysubstituted ferrocene triflones.
Domaines
Chimie
Fichier principal
comm SO2CF3 HAL.pdf (1.04 Mo)
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adsc202400834-s1-si_1.pdf (9.91 Mo)
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