Gold Catalyzed Synthesis of Substituted Furan by Intermolecular Cascade Reaction of Propargyl Alcohol and Alkyne

Abstract

Using a combination of triazole-gold (TA-Au) and copper catalysts, the substituted furan was achieved in one pot through a three-step reaction cascade. The reaction tolerates a large substrate scope with simple starting materials. The desired di-, tri-, and tetrasubstituted furans were prepared in good to excellent yields.

Regio‐ and Site‐selective Molecular Rearrangements by Homogeneous Gold Catalysis

“…demonstrated an one‐flask operation for the synthesis of furans through an intermolecular cascade reaction between propargyl alcohols and alkynes using a combination of triazole‐gold and Cu(OTf) 2 catalytic system. The in situ generated propargyl vinyl ethers undergoes Saucy‐Marbert rearrangement and the resulting allenyl‐ketone endures 5‐ exo ‐ trig cyclization to form furan products selectively [255] . Along with these outcomes, the Au(I)‐catalyzed propargyl‐Claisen rearrangement/6‐ endo ‐ trig cyclization of propargyl vinyl ethers for the regiospecific synthesis of bicyclic furopyran derivatives was also documented (Scheme 59, eq 2).…”

“…The in situ generated propargyl vinyl ethers undergoes Saucy-Marbert rearrangement and the resulting allenyl-ketone en- dures 5-exo-trig cyclization to form furan products selectively. [255] Along with these outcomes, the Au(I)-catalyzed propargyl-Claisen rearrangement/6-endo-trig cyclization of propargyl vinyl ethers for the regiospecific synthesis of bicyclic furopyran derivatives was also documented (Scheme 59, eq 2). In this work, substrates like propargyl γ-butyrolactone-2-enol ethers 261 are found to favor the 6-endo-dig regio-isomers 262 because of the limited angle strain.…”

Gold‐Catalyzed Transformations of Propargyl Alcohols and Propargyl Amines

“…Besides the synthesis of 2,5‐dihydrofurans, propargyl alcohols were also reported to be involved in the cycloaddition reaction for the preparation of furans. In 2015, Shi reported the gold‐catalyzed intermolecular cascade reaction of propargyl alcohol and alkyne, affording substituted furan as product (Scheme ) . A gold‐catalyzed nucleophilic addition of propargyl alcohol gave intermediate I , which then underwent a Saucy‐Marbet rearrangement affording allene‐ketone II .…”

Chemoselectivity in Gold(I)-Catalyzed Propargyl Ester Reactions: Insights From DFT Calculations

“…Interestingly, Shi et al developed 1,2,3-triazole (TA)-bound gold complexes as an effective catalysts (denoted as TA-Au) toward the alkynes activation (Chen et al, 2008; Liu et al, 2008; Sengupta et al, 2008; Duan et al, 2009a,b; Yan et al, 2010). This class of Au-catalysts exhibited better performance along with much lower overall costs in catalyzing the transformations of various alkynes, in comparison with the expensive NHC-Au catalysts (Duan et al, 2009a; Chen et al, 2010; Wang et al, 2010, 2011a,b,c; Hosseyni et al, 2015). More fascinating is the TA-Au catalysts even led to unique chemoselectivity.…”