Zinc‐Catalyzed Multicomponent Reactions: Easy Access to Furyl‐Substituted Cyclopropane and 1,2‐Dioxolane Derivatives

Abstract

A convenient synthesis of cyclopropyl-substituted furan derivatives by a zinc-catalyzed three-component coupling of 1,3-dicarbonylic compounds, 2-alkynals and alkenes is reported. A sequence consisting of an initial Knoevenagel condensation, cyclization, and a final cyclopropanation reaction

Zinc‐Catalysed Multi‐Component Reactions: An Overview

“…Synthesis of furan derivatives was also studied by López and co‐workers by establishing a three‐component synthesis involving cyclopropyl substitution on furan via a zinc‐catalysed protocol . Knoevenagel condensation and cyclopropanation are the major steps involved in the process ( Scheme ) .…”

Recent Advances and Perspectives in the Synthesis of HeterocyclesviaZinc Catalysis

“…Mata et al. have described an efficient synthesis of furyl‐substituted cyclopropane derivatives via a zinc‐catalyzed three‐component coupling of 1,3‐dicarbonyl compounds, alkynals and alkenes (Scheme ) . The coupling reaction is presumed to proceed via a 2‐furylzinc(II)‐carbene intermediate, which undergoes a cascade of Knoevenagel condensation, cyclization and cyclopropanation in a multicomponent manner.…”

“…The ability of ZnCl 2 to promote vinylcyclopropane rearrangements was demonstrated in 2016 for the first time and led to the synthesis of 1,2‐dioxolane derivatives (Scheme ) . 2‐Cyclopropylfuran derivatives on treatment with 50 mol% ZnCl 2 under an oxygen atmosphere in DCE at 50 °C underwent a vinylcyclopropane rearrangement‐oxygen insertion reaction affording the1,2‐dioxolane‐substituted furans in good yields.…”

An Overview of Rhodium‐Catalysed Multi‐Component Reactions

“…As an alternative, transition metal‐catalyzed MCRs have gained growing relevance where reactive functionalities are generated en route via a series of metal‐catalyzed steps . Initially, though most reactions employed Palladium as an effective catalyst, its use in modern organic synthesis has been replaced by other inexpensive and non‐toxic metals such as Ag, Zn, Cu, Co, Ni, Rh, Ru and so on. Rhodium catalysts have attained a widespread attention due to its ability to promote C−H bond activation and other bond transformations (C−X; X= C, N or O) using these C−H bonds, which are highly crucial for the generation of densely functionalized heterocyclic frameworks with greater functional and stereochemical diversity…”