posted on 2024-02-07, 23:08authored byIzabela Barańska, Liliana Dobrzańska, Zbigniew Rafiński
A new and unprecedented stereoselective synthetic approach
to δ-oxoesters
derivatives from readily available starting materials has been developed.
This method, catalyzed by N-heterocyclic carbene, involves an annulation–deoxalation
reaction of alkynyl aldehydes with 2,4-diketoesters and proceeds via
the chiral α,β-unsaturated acylazolium intermediates.
The annulation includes the in situ formation of
dihydropyranones, which undergo ring-opening methanolysis with Lewis
acid activation, followed by deoxalation to afford chiral 1,5-ketoesters
in moderate to good yields.