Straightforward Access to Isoindoles and 1,2-Dihydrophthalazines Enabled by a Gold-Catalyzed Three-Component Reaction

We describe herein a gold-catalyzed three-component reaction of o-alkynylbenzaldehydes, aryldiazonium salts, and trimethoxybenzene. This process enables the one-pot formation of valuable isoindoles and 1,2-dihydrophathalazines. The regioselectivity of the reaction is dictated by the nature of the aryldiazonium salt. Noticeably, the reaction is performed at room temperature under mild conditions and tolerates a variety of functional groups on both the o-alkynylbenzaldehyde and the aryldiazonium salt. Experimental mechanistic studies suggest that it is catalyzed by arylAu(III) species.

Design, preparation and characterization of magnetic nanoparticles functionalized with chitosan/Schiff base and their use as a reusable nanocatalyst for the green synthesis of 1H-isochromenes under mild conditions

In this study, a Schiff base complex magnetic nanocatalyst was designed and prepared. The structure of the Fe3O4@CS-SB-CaMgFe2O4 nanocatalyst was characterized using FT-IR spectroscopy, XRD, VSM, FE-SEM, EDX, elemental mapping, BET, and TGA techniques. The synthesis of 1H-isochromene compounds has attracted the attention of chemists due to their biological and medicinal properties. The 1H-isochromene derivatives were synthesized in the presence of the Fe3O4@CS-SB-CaMgFe2O4 nanocatalyst with excellent efficiency and short reaction time as well as according to the rules of green chemistry. This reaction was carried out using Fe3O4@CS-SB-CaMgFe2O4 as a catalyst to develop a simple method with low activation energy at room temperature under optimal conditions. This catalyst provides a promising route for the synthesis of 1H-isochromene multiple times through its recyclability without significant loss of catalytic activity. This nanocatalyst possesses several advantages, including cost-effectiveness, facile separation, environmental friendliness, and recyclability, for the efficient production of 1H-isochromenes. The obtained compounds were further analyzed using spectroscopic techniques, such as melting point, FT-IR, 1H NMR, and 13C NMR analyses, to confirm their structures. The spectra of the synthesized compounds were recorded and analyzed, and a plausible mechanism for their synthesis was proposed. The characterization results and structural elucidation provide valuable insights into the preparation of these compounds.

Ag(I)-catalyzed cyclization of o-alkynylacetophenones facilitated through acetal formation: synthesis of C3-naphthyl indole derivatives

A mild method for an efficient synthesis of C3-naphthyl indoles from o-alkynylacetophenones has been developed. This Ag-catalyzed transformation is assisted by the acetal formed under the reaction condition employing trimethyl orthoformate (TMOF). The role of acetal in promoting the reaction under ambient conditions has been established with control experiments. A range of C3-naphthyl indole derivatives have been synthesized in moderate to very good yields.

Diastereoselective Synthesis of Tetrahydrobenzo[b]azocines by Lu(OTf)3 Catalyzed [4 + 4] Cycloaddition of Donor–Acceptor Cyclobutanes with Anthranils

The construction of N-heterocyclic eight-membered rings remains a challenging due to unfavorable transannular strain. Herein, we report a Lu(OTf)3 catalyzed formal [4 +4] cycloaddition reaction of cyclobutane 1,1-diesters with anthranils...

Lewis acid-catalyzed [4 + 2] cycloaddition of donor–acceptor cyclobutanes with iminooxindoles: access to spiro[piperidine-3,2′-oxindoles]

A Lewis acid-catalyzed [4 + 2] cycloaddition reaction from D–A cyclobutanes and iminooxindoles, providing the corresponding spiro[piperidine-3,2′-oxindoles] under mild conditions.