Nucleophilic 5-endo-trig Cyclization of 3,3-Difluoroallylic Ketone Enolates: Synthesis of 5-Fluorinated 2-Alkylidene-2,3-dihydrofurans
摘要:
3,3-Difluoroallylic ketones readily undergo nucleophilic 5-endo-trig cyclization through their metal enolates to afford 5-fluorinated 2-alkylidene-2,3-dihydrofurans. O-Cyclization exclusively occurred via intramolecular substitution of the vinylic fluorines.
Nucleophilic 5-endo-trig Cyclization of 3,3-Difluoroallylic Metal Enolates and Enamides: Facile Synthesis of Ring-Fluorinated Dihydroheteroles
摘要:
Metal enolates and enamides bearing difluoroallylic moieties underwent nucleophilic 5-endo-trig cyclization, a process considered to be disfavored according to Baldwin's rules. Whereas no C-cyclization was observed in these reactions, O- and N-cyclization proceeded exclusively to afford 5-fluorinated 2-alkylidene-2,3-dihydrofurans and -2,3-dihydropyrroles, respectively.
Metal enolates and enamides bearing difluoroallylic moieties underwent nucleophilic 5-endo-trig cyclization, a process considered to be disfavored according to Baldwin's rules. Whereas no C-cyclization was observed in these reactions, O- and N-cyclization proceeded exclusively to afford 5-fluorinated 2-alkylidene-2,3-dihydrofurans and -2,3-dihydropyrroles, respectively.
Nucleophilic 5-endo-trig Cyclization of 3,3-Difluoroallylic Ketone Enolates: Synthesis of 5-Fluorinated 2-Alkylidene-2,3-dihydrofurans
3,3-Difluoroallylic ketones readily undergo nucleophilic 5-endo-trig cyclization through their metal enolates to afford 5-fluorinated 2-alkylidene-2,3-dihydrofurans. O-Cyclization exclusively occurred via intramolecular substitution of the vinylic fluorines.