We report a new anionic cascade for assembling 2,4-substituted benzoate esters in one pot from racemic β-fluoro-substituted conjugated tert-butylsulfinyl imines and 3-substituted methyl 2-butenoates. Dienolate formation triggers a Mannich addition… Click to show full abstract
We report a new anionic cascade for assembling 2,4-substituted benzoate esters in one pot from racemic β-fluoro-substituted conjugated tert-butylsulfinyl imines and 3-substituted methyl 2-butenoates. Dienolate formation triggers a Mannich addition followed by an amino-Cope like rearrangement, which results in immediate elimination of fluoride by a lithiated enamine. The newly formed 1,4-diene intermediate contains a highly acidic proton which is spontaneously deprotonated, leading to a facile intramolecular cyclization followed by sulfinamide group elimination and aromatization.
               
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