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A straightforward access to novel spiro[benzofuran-2,3'-pyrrolidine]-2',5'-diones based on the Rh 2 (esp) 2 -catalyzed insertion of carbenes derived from diazo arylidene succinimides (DAS) into the O-H bond of phenols is described. The initial adducts underwent a thermally promoted Claisen rearrangement followed by DABCO-catalyzed intramolecular 5- exo - trig oxa-Michael addition., (Copyright © 2022, Vepreva et al.)

The previously described α-acetyl-α-diazomethanesulfonamide was employed in a three-component reaction with azide-containing benzaldehydes and propargylamines. Besides the initial formation of the triazole core, the reaction proceeded further, in uncatalyzed fashion at room temperature and yielded, after intramolecular azide-alkyne click reaction novel, structurally intriguing bistriazoles., (Copyright © 2022, Malkova et al.)

A practically convenient and streamlined protocol for the trans -diastereoselective introduction of an aryl substituent at position 4 of the 1,4-dihydroisoquinol-3-one (1,4-DHIQ) scaffold is presented. The protocol involves direct Regitz diazo transfer onto readily available 3(2 H )-isoquinolones followed by TfOH-promoted hydroarylation by an arene molecule. Screening of the novel 1,2,4-trisubstituted 1,4-DHIQs against cancer cell lines confirmed high cytotoxicity of selected analogs, which validates this new chemotype for further investigations as anticancer cytotoxic agents., (Copyright © 2022, Dar’in et al.)

Formation of unusual unsymmetrical dimers or/and indenes via Rh 2 (esp) 2 -catalyzed decomposition of 3-diazo-2-arylidenesuccinimides has been investigated. The reaction proceeded under mild conditions, and its result was shown to strongly depend on the nature of the substituents in the diazo substrate. The new reaction provides access to dibenzoazulenodipyrrole and indenopyrrole derivatives in moderate to high yield. Dibenzoazulenodipyrroles bearing alkyl substituents at the nitrogen atom showed pronounced cytotoxocity against the A549 human lung adenocarcinoma cell line while N -aryl analogs were non-cytotoxic., (Copyright © 2022, Vepreva et al.)

N -Alkyl α-diazo-γ-butyrolactams, previously found to be unstable and to undergo unproductive dimerization to bishydrazones, were successfully converted immediately to various X-H insertion products with alcohols, aromatic amines and thiols via an in situ Rh II -catalyzed reaction. With aliphatic amines or unreactive, sterically hindered anilines, the reactions tended to yield enamine adducts., (Copyright © 2020, Eremeyeva et al.; licensee Beilstein-Institut.)

A three-component reaction involving in situ generation of propargylureas and subsequent Zn(OTf) 2 -mediated cyclocondensation with a primary amine yielded trisubstituted 2-aminoimidazoles. These findings are in contrast to the previously reported base-promoted unimolecular cyclization of propargylureas (leading to 2-imidazolones) and extend the range of Lewis acid-catalyzed azole syntheses based on N -carbonyl propargylamines.

A series of 15 benzene-fused hexahydropyrrolo[1,2- b ]isoquinolonic acids with substantial degree of steric encumbrance has been prepared via a novel variant of the Castagnoli-Cushman reaction of homophthalic anhydride (HPA) and various indolenines. The employment of a special kind of a cyclic imine component reaction allowed, for the first time, isolating a Mannich-type adduct between HPA and an imine component which has been postulated but never obtained in similar reactions.