Synthesis and Chemoselective Reactivity of 3-Aminocyclopentadienones

Abstract

This Letter describes the synthesis and chemoselective cycloaddition chemistry of 3-aminocyclopentadienones.Cyclopentadienones have been widely recognized as having a high degree of synthetic potential. [1][2][3] Unfortunately, their propensity to dimerize 1,2 has limited their use in synthesis to masked cyclopentadienones 3 or to those containing multiple aromatic rings. 4 As part of our program targeting the use of cyclopentadienones in the synthesis of complex molecules, we became interested in 3-aminocyclopentadienones 5 since the divergent electronic properties present in the two enone double bonds would provide us with the opportunity to carry out chemoselective manipulations. Outlined herein are our preliminary results that not only describe the synthesis of 3-aminocyclopentadienones but also their unique properties in cycloaddition chemistry.

Unique Metal‐Diyne, ‐Enyne, and ‐Enediyne Complexes: Part of the Remarkably Diverse World of Metal‐Alkyne Chemistry

“…Cyclopentadienones are also good synthons for polycyclic compounds (355)(356)(357)(358)(359) and polymers (360,361) and are prepared generally by alkynealkyne-CO coupling (362,363). However, most preparations of cyclopentadienones are stepwise processes involving catalysts such as CpCo(PPh 3 ) 2 (364) and RhCl(PPh 3 ) 3 (365) that mediate alkyne-alkyne coupling to give metallacyclopentadienes.…”

Cyclopentadienone Formation from β,γ-Unsaturated Cyclopentenones and Its Application in Diels–Alder Reactions

“…Cyclopentadienones (CPDs) are a family of fascinating molecules with broad applications in chemical synthesis, material science, and biological studies . They have been used in annulation reactions to release aromatic rings with multiple substituents and employed as ligands to form a range of coordination complexes, which can catalyze a series of valuable transformations . Furthermore, cyclopentadienones have been used to make biologically active natural products, including manzamenone A, chamaecypanone C, and hirsutic acid .…”

A rhodium(I)-xylyl-BINAP catalyzed asymmetric ynamide-[2+2+2] cycloaddition in the synthesis of optically enriched N,O-biaryls

“…An immense amount of efforts has led to a number of elegant synthetic methodologies to be developed adopting ynamides as a de novo functional group,1–4 and culminated in several total syntheses employing ynamides as a versatile building block 5,6. Among these efforts [Figure 1], both Witulski’s work on [2 + 2 + 2] cycloadditions of ynamides in the synthesis of indoles and carbazoles,7,8 and Rainier’s formal [2 + 2 + 2] cycloaddition9 inspired us10,11 to develop a new approach toward chiral N,O -biaryls through a [2 + 2 + 2] cycloaddition of conjugated aryl ynamides with diynes 12–14. This concept was envisioned at the heel of our success in the synthesis of conjugated aryl ynamides via Sonogashira cross-coupling 15.…”