Annulation Reaction of 3-Acylmethylidene Oxindoles with Huisgen Zwitterions and Its Applications in the Syntheses of Pyrrolo[4,3,2-de]quinolinones and Marine Alkaloids Ammosamides

Abstract

A novel annulation reaction of 3-acylmethylidene oxindoles with Huisgen zwitterions is unveiled that leads to an unprecedented synthetic method for complex pyrrolo[4,3,2-de]quinolinones and marine alkaloids ammosamides A-C. This method features simplicity, high efficiency, and broad substrate scope and is accordingly anticipated to significantly facilitate the preparation and bioassay of the relevant pyrroloquinoline alkaloids and their analogues.

Copper-Catalyzed Chemoselective and Enantioselective Friedel–Crafts 1,2-Addition of Pyrrole with β,γ-Unsaturated α-Ketoesters

“…Commercially available pyrrole should be distilled for the use of the reactions. Ligands , and various β,γ-unsaturated α-ketoesters 2 were prepared according to literature procedures.…”

Strategies and Methods for the Synthesis of 2‐Pyrazolines: Recent Developments (2012–2022)

“…Since then, annulation and condensation reactions of Huisgen zwitterions with electrophiles have been utilized to provide various nitrogen heterocycles, such as pyrroles, furans, [91a] quinolinones, [91b] triazines [91c] thiazolopyridines, [91d] oxadiazoles, [91e] triazolines, [91f] and even acyclic hydrazones [91g] . Annulations with acyl cyanides, [92a] chalcones, [92b] ynones, [92c] and cinnamils [92d] have given access to functionalized 3‐pyrazolines.…”

Direct Synthesis of β,γ-Unsaturated α-Keto Esters from Aldehydes and Pyruvates

“…In the previous report, it was prepared only by Wittig reaction in a similar yield. 20 In summary, we have developed two practical methods to synthesize β,γ-unsaturated α-keto esters directly from aldehydes and pyruvates through aldol condensation promoted by BF 3 •Et 2 O in the presence of Ac 2 O or by Ti(OEt) 4 under mild conditions. Both methods could be applied in most of aromatic aldehydes to afford the target products in moderate to excellent yields.…”