Anionic Amino-Cope Rearrangement Cascade Synthesis of 2,4-Substituted Benzoate Esters from Acyclic Building Blocks

We report a new anionic cascade for assembling 2,4-substituted benzoate esters in one pot from racemic ig-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.

Automated summary

The reported anionic cascade reaction enables the efficient synthesis of 2,4-substituted benzoate esters through multiple catalytic steps including Mannich addition and amino-Cope rearrangement. The entire reaction process is fast and effective, providing new possibilities in the field of chemical synthesis.