Tin Powder-Promoted Cascade Condensation/Allylation/Lactamization: Synthesis of Isoindolinones and Pyrazoloisoindol-8-ones

Abstract

An efficient tin powder-promoted cascade condensation/allylation/lactamization of 2-formylbenzoic acids, hydrazides, and allyl bromides was developed for the synthesis of isoindolinones in good to excellent yields under mild conditions without any other additives or catalysts. Further manipulation of isoindolinones by iodocyclization process afforded the tricyclic tetrahydro-8H-pyrazolo[5,1a]isoindol-8-one derivatives, which could be converted into more complicated tetracyclic tetrahydro-4H-azirino[1′,2′:2,3]pyrazolo[5,1-a]isoindol-4-ones.

Synthesis of 1‐(3H)isobenzofuranone compounds by tin powder promoted cascade condensation reaction

“…Finally, the reaction mechanism was proposed based on the experimental results and literature (Scheme 6). [ 10a, 11a ] First, allyl bromides 2 reacted with tin powder to generate in situ the allyl tin bromides 12 [ 13 ] which underwent γ ‐addition reaction with 2‐formylbenzoic acids 1 to give intermediates 14 . The hydrolysis of intermediates 14 produced the final target products 4 .…”

“…In our research group, we are interested in metal tin‐mediated organic reactions due to their good stability toward heat, hydrolysis, and oxidants with good tolerance to functional groups and high selectivity in reactions. [ 10 ] We have developed the tin‐powder promoted one‐pot reaction of allyl bromides or 2‐bromoacrylic acid esters, carbonyl compounds and hydrazides to afford homoallylic N ‐acylhydrazines or α ‐methylene‐ γ ‐lactams [ 10a, 11 ] . In addition, we also investigate the C‐C coupling reaction of in‐situ formed allyltin bromide with benzylic carbocations.…”

Ethyl 5-Formyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-4-carboxylate: Synthesis, Crystal Structure, Hirshfeld Surface Analysis, and DFT Calculation

“…For example, new protocols for the synthesis of 3-difluoroalkyl phthalides [1], 3-benzylphthalides [2], 3-(1 -indolyl)phthalides [3], and electrochemical protocol for isoindolinones [4] were developed. Syntheses of (+)-Rubellin C [5], benzo[f]pyrrolo [1, 2-a] [1,4] diazepines [6], fluorinated isocoumarines [7], furo [2,3-d]pyridazines [8], furo [3,4-c]pyridines [9], 1-oxo-9H-thiopyrano [3,4-b]indoles [10], pyrazoloisoindoles [11], phthalazines [12] and isothiocoumarines [13] were studied. ortho-Formyl acids were used for the synthesis of biologically active compounds with anticancer potential [14]; PROTACs E3 ubiquitin ligase inhibitor [15] and MDM2 [16] degrades; STING [17] and PKM2 [18] modulators; inhibitors of Eg5 [19], SIRT1 and SIRT2 [20], 15lipoxygenase-1 [21] and pyruvate kinase activators [22].…”

Intermolecular Hydrazinative Halogenation of Alkenes with Potassium Halides as Nucleophilic Halogen Sources: Modular Entry to Phenelzine Derivatives

“…In these reactions, carbon-, nitrogen-, ,, oxygen-, or sulfur-centered groups could be introduced into the parent alkenes along with hydrazination. In contrast, intermolecular hydrazinative halogenation of alkenes by incorporating halogen into the parent alkenes has been rarely studied, although the formed halogenated hydrazines can serve as more promising building blocks in synthesis . To the best of our knowledge, there is only one example related to this aspect until now, in which intermolecular hydrazinative chlorination of alkene gives the desired product in moderate yield using stoichiometric highly toxic tin­(IV) chloride as a promoter and a chlorine source. , Intermolecular hydrazinative bromination and iodination of alkenes have not been developed yet due to the lack of appropriate methods.…”