Furans propargyl vinyl ethers

Au-Catalyzed reaction of propargyl vinyl ethers furnished tri- and tetrasubstituted furans in high yields. The reaction proceeded through cyclization of 2-allenyl-13-dicarbonyl intermediates produced from propargyl-Claisen rearrangement <05OL3925>. [Pg.198]

Scheme 1 The principle of furan synthesis from propargyl vinyl ethers.

TL4697, 08SC2607). The propargyl vinyl ethers were then converted with palladium(II) chloride and copper(I) iodide in the presence of tetrabu-tylammonium chloride into bicyclic furans 26 in moderate to good yields. [Pg.10]

The related Gosteli-Claisen rearrangement of 2-alkoxycarbonyl-substituted propargyl vinyl ethers can also be catalyzed by cationic gold(I) complexes and provides highly substituted furan derivatives. ... [Pg.468]

Eq. 3.6 shows the direct preparation of furan derivative (19) by the successive treatment of vinyl ethers with propargyl alcohol/NBS, radical cyclization with Bu3SnH/AIBN, and lastly, aromatization with p-TsOH. [Pg.61]

Kirsch et al. reported that vinyl propargyl ethers 36 could be converted into the densely substituted furans 38 via the Au(I)-catalyzed cycloisomerization reaction (Scheme 8.17) [125] A variety of substituted furans 38 (Table 8.1) could be obtained under very mild reaction conditions at only 2 mol% catalyst loading. It is believed that this cascade process begins vith the Au(I)-catalyzed Claisen-type rearrangement of 36 leading to the formation of skipped allenyl ketone 37, vhich, upon the Au(I)-catalyzed 5-exo-dig-cyclization, provides furan 38. [Pg.235]

Formylfurans are obtained in a one-step procedure from propargyl alcohols and electron-deficient alkynes (Scheme 4-289). This domino process involves the nucleophilic addition of the propargyl alcohol to the electron-deficient alkyne forming vinyl propargyl ethers. An iron(lIl)-catalyzed cyclization, rearrangement and oxidation domino process follows to furnish the furan-2-carbaldehydes. ... [Pg.717]