Recent Advances on Piancatelli Reactions and Related Cascade Processes

Abstract

The Piancatelli reaction, which is the rearrangement of 2-furylcarbinol to cyclopentenone, involves a key furanoxonium ion intermediate and a furan ring opening-4π electrocyclization process. In recent years, the original oxa-Piancatelli reaction has been extended to a large family of aza- and carbo-Piancatelli reactions and related cascade processes, providing a powerful platform for the construction of diverse functionalized cyclopentenones and polycyclic cyclopentanones. Meanwhile, chiral Brønsted/Lewis acid based catalytic asymmetric approaches to Piancatelli reactions have also been achieved for the assembly of highly valued chiral cyclopentenone scaffolds. In this short review, we present an overview of the recent developments in these areas and focus primarily on reports published in the last five years.1 Introduction2 Diastereoselective Oxa-, Aza- and Carbo-Piancatelli Reactions3 Diastereoselective Cascade Piancatelli Reactions4 Asymmetric Piancatelli Reactions and Related Cascade Processes5 Miscellaneous Furanoxonium Ion-Based Rearrangements6 Conclusion

A Comprehensive Review on Metal Catalysts for the Production of Cyclopentanone Derivatives from Furfural and HMF

“…Both hydrogenation and acid active centers are needed for the reaction. The mechanism for the Piancatelli rearrangement is shown in Scheme 4 [ 58 , 59 , 60 , 61 ]. The reaction typically occurs in water catalyzed by acid.…”

Rapid Access to Densely Functionalized Cyclopentenyl Sulfoximines through a Sc-Catalyzed Aza-Piancatelli Reaction

“…Separately, the aza-Piancatelli reaction, a Nazarov-type electrocyclization, has emerged as a powerful tool for assembling high-value-added 4-aminocyclopentenones from feedstock furans in a single step with complete diastereocontrol. , Derivatizations of these compounds enable the rapid construction of biologically relevant aminocyclopentitols. − Densely functionalized cyclopentylamines are core motifs in a variety of natural and synthetic products such as peramivir, pactamycin, and agelastatin A as well as key building blocks in synthesis (Scheme B) . Despite their growing importance, the preparation of cyclopentylamines remains challenging, often requiring lengthy syntheses.…”

Asymmetric Construction of Functionalized Cyclopenta[b]pyrrolines via Cascade Aza-Piancatelli/Hydroamination Reactions

“…In recent years, the Piancatelli rearrangement triggered cascade cyclization has become a powerful tool for the rapid construction of cyclopentanone-based polycyclic compounds. − In continuation of our interest in developing asymmetric variants of these reactions and related cascade processes, herein, we present a chiral Brønsted acid and transition metal cooperatively catalyzed cascade aza-Piancatelli rearrangement/hydroamination reaction (Scheme b). This dual catalytic method harnesses readily accessible alkynyl-functionalized tertiary furylcarbinols as furanoxonium precursors, which undergo a chiral Brønsted acid catalyzed aza-Piancatelli reaction with aniline nucleophiles to generate the key alkynyl-functionalized cis -fused cyclopentenone intermediates, followed by a Pd-catalyzed hydroamination process, enabling the efficient construction of diverse densely functionalized cyclopenta[ b ]pyrrolines with multiple chiral elements in high stereocontrol.…”