Piancatelli Rearrangement Research Articles

ChemInform Abstract: Efficient Synthesis of 4‐Hydroxycyclopentenones: Dysprosium(III) Triflate Catalyzed Piancatelli Rearrangement.

AbstractThe Piancatelli rearrangement of a small series of furylcarbinols is examined.

A convenient preparation of (S)-(−)-4-hydroxy-2-methylcyclopent-2-en-1-one and its application as a chiral synthetic equivalent of 2-methylcyclopent-2-en-1-one in the terpenoid synthesis

A method for the preparation of (S)-4-hydroxy-2-methylcyclopent-2-en-1-one from 1-(2-furyl)ethanol using modified Piancatelli rearrangement and enzymatic kinetic resolution of the racemate was developed. An application of O-protected derivatives of 4-hydroxy-2-methylcyclopent-2-en-1-one to terpenoid synthesis through tandem conjugate addition of allyl-metal reagents, enolate trapping, and consecutive Mukaiyama–Michael addition was studied. An optically active azulene derivative useful for terpenoid synthesis was efficiently synthesized.

ChemInform Abstract: Lewis Acid Catalyzed Rearrangement of Furylcarbinols: The Aza‐ and Oxa‐Piancatelli Cascade Reaction.

The acid-catalyzed rearrangement of furylcarbinols is utilized to access 4,5-substituted cyclopentenones. This cascade transformation began with implementing anilines, as an alternative nucleophile to water as used in the Piancatelli rearrangement, and has currently progressed through an intramolecular rearrangement to the use of alcohols as the nucleophile.

ChemInform Abstract: The Piancatelli Rearrangement: New Applications for an Intriguing Reaction

AbstractReview: 60 refs.

Chemoenzymatic approach to optically active 4-hydroxy-5-alkylcyclopent-2-en-1-one derivatives: an application of a combined circular dichroism spectroscopy and DFT calculations to assignment of absolute configuration.

A series of representative optically active derivatives of 4-hydroxy-5-alkylcyclopent-2-en-1-one were prepared from the respective 2-furyl methyl carbinols via the Piancatelli rearrangement followed by the enzymatic kinetic resolution of racemates. Applicability of chiroptical methods (experimental and calculated electronic circular dichroism [ECD] and vibrational circular dichroism [VCD] spectra) to determine the absolute configuration of both stereogenic centers in 4-hydroxy-5-methylcyclopent-2-en-1-one was demonstrated. It was also demonstrated that the concurrent application of ECD and VCD spectroscopy can be used for the determination of the configuration of two stereogenic centers.

Efficient synthesis of 4-hydroxycyclopentenones: dysprosium(III) triflate catalyzed Piancatelli rearrangement

4-Hydroxycyclopentenones represent a privileged scaffold in chemical synthesis. A dysprosium(III) trifluoromethanesulfonate catalyzed rearrangement of furylcarbinols to 4-hydroxycyclopentenones via a 4π electrocyclization has been developed. The catalytic Piancatelli rearrangement affords a single trans-diastereomer from both aryl and alkyl substituted furylcarbinols.

Lewis Acid Catalyzed Rearrangement of Furylcarbinols: The Aza- and Oxa-Piancatelli Cascade Reaction

The acid-catalyzed rearrangement of furylcarbinols is utilized to access 4,5-substituted cyclopentenones. This cascade transformation began with implementing anilines, as an alternative nucleophile to water as used in the Piancatelli rearrangement, and has currently progressed through an intramolecular rearrangement to the use of alcohols as the nucleophile.

The Piancatelli Rearrangement: New Applications for an Intriguing Reaction

Nearly forty years ago, at the University of Rome, Giovanni Piancatelli and co-workers discovered the acid-catalyzed water-mediated rearrangement of 2-furylcarbinols into 4-hydroxycyclopentenones. These motifs are core components of several pharmacologically active compounds and precursors of many natural products. The main features of this reaction are the simple experimental conditions, the stereochemical outcome and the generality of the procedure. Consequently, a re-emergence of this reaction has been seen recently, including developments of the Piancatelli rearrangement with some interesting inter- and intramolecular variants. This review will mainly focus on the general aspects of the reaction along with its more recent applications.

ChemInform Abstract: Rapid and Stereoselective Synthesis of Spirocyclic Ethers via the Intramolecular Piancatelli Rearrangement.

The first example of a Piancatelli rearrangement of alcohols is demonstrated utilizing dysprosium(III) triflate as a catalyst to access oxaspirocycles in a highly diastereoselective manner. The cascade reaction constructs the spirocyclic ether ring system and the tertiary stereocenter in a single operation and is experimentally easy to perform.

Metal‐Free Rearrangement of Spirofurooxindoles into Spiropentenoneoxindoles and Indoles: Implications for the Mechanism and Stereochemistry of the Piancatelli Rearrangement

AbstractSpirofurooxindoles derived from α‐furylcarbinols were rearranged into spirocyclopentenoneoxindoles exclusively or as a mixture of spirocyclopentenoneoxindoles and indoles under different reaction conditions. Along with our previous studies, the stepwise C‐Piancatelli rearrangement has been presented for the first time.

Rapid and Stereoselective Synthesis of Spirocyclic Ethers via the Intramolecular Piancatelli Rearrangement

The first example of a Piancatelli rearrangement of alcohols is demonstrated utilizing dysprosium(III) triflate as a catalyst to access oxaspirocycles in a highly diastereoselective manner. The cascade reaction constructs the spirocyclic ether ring system and the tertiary stereocenter in a single operation and is experimentally easy to perform.

The Manufacture of a Homochiral 4-Silyloxycyclopentenone Intermediate for the Synthesis of Prostaglandin Analogues

A process is described for the synthesis of kilogram quantities of homochiral 4-silyloxycyclopentenone (R)-1, a key intermediate useful for the synthesis of a plurality of prostaglandin analogue drugs. Cyclopentenone (R)-1 was synthesized in 14 isolated steps from furfural. Key steps in the synthesis include a Wittig reaction, Piancatelli rearrangement, and an enzymatic resolution featuring in situ recycling of the undesired enantiomer furnishing the desired homochiral alcohol in ≥99.5% ee. As a retort to the unsatisfactory coformation of about 8% at best of the trans-olefin in the Wittig reaction, a change to the order of several steps and the identification of a recrystallisable, amine salt derivative, 2, allowed the unwanted isomer to be controlled to as low as 0.2%.

Synthesis of the core framework of the proposed structure of sargafuran

Synthesis of 2-homoprenyl-1-methyl-3-(5-methylfuran-2-yl)cyclopenta-2,4-dien-1-ol, the core framework of the proposed structure of the brown alga derived natural product sargafuran, was achieved in six steps from the commercially available 5-methylfurfural via the Piancatelli rearrangement of furylcarbinol. The concise synthetic route to the 1,2,3-trisubstituted cyclopentadienol is established. However, the 1H and 13C NMR spectral data of the synthetic analog of sargafuran suggest that the originally proposed structure of sargafuran must be incorrect. In addition, the structure of the natural sargafuran is also discussed.

Selective, potent PPARγ agonists with cyclopentenone core structure

A series of analogues of the PPARγ ligand 15-deoxy-Δ 12,14-PGJ 2 have been synthesized by functionalization of a 5-alkyl-4-hydroxycyclopentenone core structure obtained by Piancatelli rearrangement of precursor furylcarbinol. Transient transactivation assays indicate that analogues 18 and 20 are selective nanomolar agonists of PPARγ. This subtype selectivity is lost in derivatives ( 23, 24) with an alkynyl (oct-1-yn) chain at the C3 position, although the cyclopentenone derivative with cis relative configuration ( 23) showed greater affinity for PPARα.