880096-90-2Relevant academic research and scientific papers
Dianionic Phase-Transfer Catalyst for Asymmetric Fluoro-cyclization
Egami, Hiromichi,Niwa, Tomoki,Sato, Hitomi,Hotta, Ryo,Rouno, Daiki,Kawato, Yuji,Hamashima, Yoshitaka
, p. 2785 - 2788 (2018)
Inspired by the dicationic nature of the electrophilic fluorinating reagent, Selectfluor (1), we rationally designed a series of dicarboxylic acid precatalysts (2), which, when deprotonated, act as anionic phase-transfer catalysts for asymmetric fluorination of alkenes. Among them, 2a having the shortest linker moiety efficiently catalyzed unprecedented 6-endo-fluoro-cyclization of various allylic amides, affording fluorinated dihydrooxazine compounds with high enantioselectivity (up to 99% ee). In addition to cyclic substrates, acyclic trisubstituted alkenes underwent the reaction with good diastereoselectivity, whereas low diastereoselectivity was observed for linear disubstituted alkenes. Results suggest that the reaction proceeds via a fluoro-carbocation intermediate.
