3‐Functionalized Tetronic Acids From Domino Rearrangement/Cyclization/Ring‐Opening Reactions of Allyl Tetronates

Abstract

Abstract Allyl tetronates 1 thermally rearrange to stable 3‐(spirocyclopropyl)dihydrofuran‐2,4‐diones 2 (R 3 = H, Aryl), which can be ring‐opened with O‐, N‐, S‐ and C‐nucleophiles to give 3‐substituted tetronic acids 3 − 7 . Compounds 2 with R 3 = Alkyl are not isolable, but are interceptable intermediates in formal [2,3]‐sigmatropic rearrangements of allyl tetronates. The vinylogous hexadienyl tetronate 17 undergoes a different domino [3,5]‐rearrangement/cyclization reaction to give the 2 H ,5 H ‐furano[4,3‐ b ]oxepin‐6‐one 19 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)