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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., Competing Interests: The authors declare no conflict of interest.

A method for the synthesis of isoindoline derivatives was developed based on a domino reaction involving a donor-acceptor cyclopropane containing a bromomethyl group in the ortho position of the aromatic substituent and structurally varied primary amines (anilines, benzylamines, cycloalkylamines). It was shown that the resulting N-benzyl-1,3-dihydroisoindole under hydrogenolysis conditions at room temperature underwent selective cleavage of the exocyclic N–CH2Ar bond followed by in situ lactamization to form benzo[b]pyrrolizidinone. The same product was obtained in a domino reaction starting with reduction of the azidomethyl group at the ortho position of the donor aromatic substituent. Similarly, the generation of the o-2-aminoethyl group was accompanied by two successive cyclization reactions leading to the formation of benzo[e]indolizidinone. [ABSTRACT FROM AUTHOR]