Iron-Catalyzed Domino Process for the Synthesis of α-Carbonyl Furan Derivatives via One-Pot Cyclization Reaction

Abstract

The Fe(ClO(4))(3)-catalyzed intramolecular rearrangement/cyclization/oxidation reaction sequence for the synthesis of alpha-carbonyl furan derivatives from electron-deficient alkynes and 2-yn-1-ols is reported.

Synthesis of Dihydroisobenzofuran Carboxaldehyde Derivatives by a Silver‐Catalyzed Sequential Protodesilylation/Cyclization/Oxidation Reaction

“…After desilylation, we propose that the reaction proceeds through a mechanism of alkyne activation by the metal followed by an intramolecular 5‐exo‐dig cyclization then oxidation (Figure , path A ), which is analogous to previously proposed mechanisms. [5a], [5b], , , Formation of the diketone product 4 likely occurs from hydrolytic cleavage of the 5‐membered oxocarbenium ring ( path B ) based on the observed regiochemistry of the hydrated product.…”

“…Currently, the construction of dihydroisobenzofuranones, such as the total synthesis polyketide 1 , involves numerous synthetic steps . Only a limited number of synthetic methods have been reported for the generation of α‐carbonyl furan derivatives and reports on the synthesis of α‐carbonyl bicyclic furans, such as isobenzofurans, are scarce . Therefore, the development of efficient methods to quickly and efficiently arrive at this core structure would be beneficial for accessing this important class of biologically relevant molecules.…”

FeCl3⋅6H2O‐Catalyzed Intermolecular‐Cascade Cyclization of Acetoacetanilide: Aldehyde‐Tuned Synthesis to Valuable 2‐Pyridone Analogues

“…[2] Transition-metal-catalyzed selective functionalization and cyclization are emerging as the major solution for atom-and step economical direct organic synthesis. [7] Recently, iron complexes, especially FeCl 3 , have been rightly employed as useful green catalysts for selective C À H functionalization, [8] C À C and C À N bond formation, [9] and cyclization [10,11] processes. However, the cyclization reactions are limited to intramolecular processes, requirement of halide synthons, difficultly accessible predesigned precursors, and/or harsh reaction conditions.…”

Metal-catalyzed Furan Synthesis. A Review

“…85,86 Jiang has recently published an Fe-catalyzed process which generally gives good yields of furans and requires a relatively inexpensive catalyst (Scheme 34). 87 The authors presented a one-pot process whereby DABCO, or tributylphosphine, catalyzed the addition of propargyl alcohols to activated alkynes and the resulting propargyl vinyl ethers were cyclized to the furan by the iron catalyst. The iron species activates the alkyne to nucleophilic attack from the alkene, and the subsequent heterocycle collapses to form an allene intermediate which re-cyclizes to give the furan after loss of the metal and aromatization.…”

“…87 4, 177.5, 159.8, 150.3, 137.0, 133.6, 130.7, 129.7, 128.7, 128.6, 128.2, 128.1, 123.7, 122.7 Zhang and co-workers have reported the Rh-catalyzed rearrangement of 1-(1-alkynyl)oxiranyl ketones to furans which proceeds through an unexpected C-C bond cleavage (Scheme 35). 88 The authors propose two mechanisms for this process.…”