Relieving the stress together: annulation of two different strained rings towards the formation of biologically significant heterocyclic scaffolds

Banerjee

et al. 2023

Chemistry A European J

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Three‐membered carbocyclic‐ and heterocyclic ring structures are versatile synthetic building blocks in organic synthesis owing to their biological importance. Also, the inherent strain of these three‐membered rings led to their ring‐opening functionalization via C‐C, C‐N, and C‐O bond cleavage. Traditional synthesis and ring‐opening methods of these molecules require the usage of acid catalysts or transition‐metals. Recently, electroorganic synthesis has emerged as a powerful tool for initiating new chemical transformations. In this review, the synthetic and mechanistic aspects of electro‐mediated synthesis and ring‐opening functionalization of three‐membered carbo‐ and heterocycles are highlighted.

Section: Introductionmentioning

confidence: 99%

“…are multifaceted constituents of synthetic organic chemistry [1] . Scheme 1 sums up the ring strains, among which cyclopropene acquires the highest ring strain of 55.7 kcal mol −1 [2] …”

Section: Introductionmentioning

confidence: 99%

Electrochemical Synthesis and Reactivity of Three‐Membered Strained Carbo‐ and Heterocycles

Banerjee

et al. 2023

Chemistry A European J

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“…Although many methods for the γ-lactam synthesis are known [ 15 , 16 , 17 , 18 ], the development of new and simple strategies that also make it possible to introduce desired substituents into the resulting products remains an urgent task. Our interest in this problem is related to the possibility of solving it using the donor–acceptor (DA) cyclopropane [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ] reactivity, which has been the subject of our studies in recent years [ 27 , 28 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 1,5-Substituted Pyrrolidin-2-ones from Donor–Acceptor Cyclopropanes and Anilines/Benzylamines

et al. 2022

We developed a straightforward synthetic route to pharmacologically important 1,5-substituted pyrrolidin-2-ones from donor–acceptor cyclopropanes bearing an ester group as one of the acceptor substituents. This method includes a Lewis acid-catalyzed opening of the donor–acceptor cyclopropane with primary amines (anilines, benzylamines, etc.) to γ-amino esters, followed by in situ lactamization and dealkoxycarbonylation. The reaction has a broad scope of applicability; a variety of substituted anilines, benzylamines, and other primary amines as well as a wide range of donor–acceptor cyclopropanes bearing (hetero)aromatic or alkenyl donor groups and various acceptor substituents can be involved in this transformation. In this process, donor–acceptor cyclopropanes react as 1,4-C,C-dielectrophiles, and amines react as 1,1-dinucleophiles. The resulting di- and trisubstituted pyrrolidin-2-ones can be also used in subsequent chemistry to obtain various nitrogen-containing polycyclic compounds of interest to medicinal chemistry and pharmacology, such as benz[g]indolizidine derivatives.

“…Over the years, various strained carbo- and heterocycles have been studied extensively to synthesize a myriad of biologically and pharmaceutically important molecular architectures . However, methodologies exploiting a pair of different strained rings have remained underdeveloped . 3-Donor cyclobutanones are one of the important classes of four-membered carbocycles which can generate a 1,4-zwitterionic intermediate in the presence of Lewis acid by regioselective cleavage of C2–C3 bond .…”

Section: Introductionmentioning

confidence: 99%

“…1 However, methodologies exploiting a pair of different strained rings have remained underdeveloped. 2 3-Donor cyclobutanones are one of the important classes of four-membered carbocycles which can generate a 1,4-zwitterionic intermediate in the presence of Lewis acid by regioselective cleavage of C2−C3 bond. 3 Several cycloadditions, rearrangement, and ring-opening reactions have been explored in the past few years using these fourmembered synthons.…”

Section: ■ Introductionmentioning

confidence: 99%

Merging Two Strained Carbocycles: Lewis Acid Catalyzed Remote Site-Selective Friedel–Crafts Alkylation of in Situ Generated β-Naphthol

2022

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Lewis acid catalyzed tandem activation of the two smallest carbocycles, 3-ethoxy cyclobutanones, and donor–acceptor cyclopropanes has been demonstrated. The diphenyl-substituted 3-ethoxy cyclobutanone rearranges itself by intramolecular cyclization for the in situ generation of 1-phenyl 2-naphthol, which further undergoes remote site-selective Friedel–Crafts alkylation with donor–acceptor cyclopropane to synthesize a series of γ-naphthyl butyric acid derivatives. Further control experiments for mechanistic investigations and synthetic applications have also been carried out.