An inorganic base promoted metal-free formal alkenylation and amination of 2-nitrobenzofurans is established with fumaric acid amide ester derivatives. The cascade strategy provides the 2-alkenyl and 3-amino substituted benzofurans via Michael addition/cyclization/nitrous acid elimination/N-demethoxylation/C−N bond cleavage and isomerization sequence. The desired 2-(3-aminobenzofuran-2-yl)malonate derivatives are obtained in moderate-to-good yields with high stereoselectivity under mild reaction conditions (up to 71 % yield and >20 : 1 Z : E). The structure of the products is assigned from the single crystal x-ray structural analysis.
|Publication status||Published - 2023 Jan 9|
- Furmaric acid amide ester
- Nitrous acid elimination
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