Cu(OAc)₂-Promoted Cascade Carboamination/Oxidative Cyclization of C-Acylimines with Alkenes

Abstract

A Cu(OAc)2-promoted cascade carboamination/oxidative cyclization of alkenes with α-imino esters has been explored. This transformation provides a concise approach to rapid assembly of 2-oxo-3-iminopyrrole derivatives in moderate to good yields.

BF3/nano-sawdust as a green, biodegradable and inexpensive catalyst for the synthesis of highly substituted dihydro-2-oxopyrroles

“…FT-IR spectra were recorded on an This journal is © The Royal Society of Chemistry 2015 attenuated total reectance-Fourier transform infrared (ATR-FTIR) spectrophotometer (Bruker, Eqinox 55). 1 H NMR and 13 C NMR spectra were recorded at 400 MHz and 100 MHz, respectively, on a BrukerDXR-400 spectrometer using CDCl 3 as solvent and tetramethylsilane as the internal standard. Mass spectra (MS) were recorded on a FINNIGAN-MAT 8430 mass spectrometer, operating at an ionization potential of 70 eV.…”

“…Due to the wide range in applications of dihydro-oxopyrrole derivatives in pharmaceuticals, agrochemicals, and natural products, their synthesis remains an area of intense current interest. A number of synthetic routes have been developed for the synthesis of dihydro-oxopyrrole, including the rutheniumcatalyzed reaction of a,b-unsaturated imines with carbon monoxide and ethylene, 11 the reaction of isocyanides, dialkylacetylenedicarboxylates, and benzoyl chlorides, 12 the carboamination/oxidative cyclization of C-acylimines with alkenes, 13 the transannulation of 1-sulfonyl-1,2,3-triazole with ketene silylacetal, 14 the reaction of acetylene with imines and CO 2 , 15 the Pd-catalyzed cyclization of ethyl glyoxalate and amines 16 and the reaction of a-cyanomethyl-b-ketoesters and alcohols. 17 Among these versatile synthetic methods, multicomponent reactions (MCRs) have attracted particular attention; 18 a few methods have been reported for the synthesis of dihydro-2-oxopyrroles using MCRs such as the four-component reaction of dialkylacetylenedicarboxylate, aldehyde, and amines.…”

α-Imino Esters in Organic Synthesis: Recent Advances

“…Enamine 671b was transformed into final desired products 667a by nucleophilic addition to another α-imino ester to generate 672 and subsequent tautomerization/intramolecular cyclization to 673, followed by oxidation (Scheme 171). 316 3,8-Dioxo-1,4-diazaspiro [4.5]deca-1,6,9-triene-2-carboxylate derivatives 675 were prepared in 40−90% yields, via oxidative cyclization of 2-(N-phenylcarbamoyl)-2-iminoacetates 674, using TBAI (1.2 equiv) and tert-butyl hydroperoxide (TBHP, 1.9 equiv) in DCE at 80 °C, under an oxygen atmosphere. The proposed reaction mechanism involves the iodine mediated generation of the t-BuO radical, which abstracted a hydrogen atom from 2-(N-phenylcarbamoyl)-2-iminoacetates 674, to give iminyl radical 677, which underwent ipso-5-exo cyclization to afford radical 678.…”

Decatungstate‐Photocatalyzed Functionalization of α‐Imino Esters for the Preparation of Unnatural α‐Amino Acid Derivatives

“…The addition of radical intermediates is currently an underdeveloped pathway (Scheme 1a, right part in red), despite the involvement of a radical‐mediated reaction course has been claimed in a handful of nucleophilic additions involving organometallics based on B, [2] Zn [3] and Cu [4] . A seminal example of radical functionalization methodologies described the alkylation of α‐hydrazono esters with alkyl iodides in the presence of Mn 2 (CO) 10 and InCl 3 under irradiation conditions to give the corresponding α‐aminoesters [5] .…”