Synthesis of 4-(Trifluoromethyl)cyclopentenones and 2-(Trifluoromethyl)furans by Reductive Trifluoroacetylation of Ynones

Abstract

Reductive introduction of a fluorine-containing carbon block to readily available conjugated ynones, followed by intramolecular cyclization, successfully gave the corresponding trifluoromethylated cyclopentenones or trifluoromethylated furans in good yields through a simple two-step protocol. The key compound in carbon-carbon bond formation by magnesium-promoted reduction is ethyl trifluoroacetate, which has been rarely used as a fluorine-containing carbon source, especially to electron-deficient carbon atoms in organic synthesis.

A Simple Protocol from Benzalacetones to 1,1,1‐Trifluoro‐2,5‐diketones and 2‐(Trifluoromethyl)furans by Reductive Trifluoroacetylation

“…We reported a variety of synthesis of fluorinated organic compounds by use of ethyl trifluoroacetate as a fluorinated reagent through magnesium‐promoted reduction of aromatic conjugated system . In our recent research, we disclosed a useful two‐step protocol to synthesize 4‐(trifluoromethyl)cyclopentenones and 2‐(trifluoromethyl)furans through reductive trifluoroacetylation of aromatic ynones and subsequent cyclization …”

Selective Introduction of Trifluoroacetyl Group to β‐ and δ‐Position of Aromatic Conjugated Esters: Facile Synthesis of Fluorine‐containing Keto Esters

“…We also developed synthetic methods of partially fluorinated compounds by ethyl trifluoroacetate as a fluorinated carbon source . Recently, we reported a simple two‐step protocol to synthesize 4‐trifluoromethylcyclopentenones and 2‐trifluoromethylfurans from the reductive cross‐coupling reaction of conjugated ynones with ethyl trifluoroacetate …”

Synthesis of 3-Amino-5-fluoroalkylfurans by Intramolecular Cyclization

“…The second strategy, circumventing those drawbacks, relies on the use of fluorinated building blocks during the heterocyclization. A review of the synthesis of fluoro and perfluoroalkyl furans was published in 2010, and a variety of other methods have been developed since, which are in most cases limited to -CF 3 furans. − …”