Chemodivergent assembly of ortho-functionalized phenols with tunable selectivity via rhodium(III)-catalyzed and solvent-controlled C-H activation

Development of novel transition metal-catalyzed synthetic approaches for the synthesis of a dihydrobenzofuran nucleus: a review

The synthesis of dihydrobenzofuran scaffolds bears pivotal significance in the field of medicinal chemistry and organic synthesis. These heterocyclic scaffolds hold immense prospects owing to their significant pharmaceutical applications as they are extensively employed as essential precursors for constructing complex organic frameworks. Their versatility and importance make them an interesting subject of study for researchers in the scientific community. While exploring their synthesis, researchers have unveiled various novel and efficient pathways for assembling the dihydrobenzofuran core. In the wake of extensive data being continuously reported each year, we have outlined the recent updates (post 2020) on novel methodological accomplishments employing the efficient catalytic role of several transition metals to forge dihydrobenzofuran functionalities.

Chemodivergent Photocatalyzed Heterocyclization of Hydrazones and Isothiocyanates for the Selectivity Synthesis of 2-Amino-1,3,4-thiadiazoles and 1,2,4-Triazole-3-thiones

A photocatalytic chemodivergent reaction for the selectivity formation of C-S and C-N bonds in a controlled manner was proposed. The reaction medium, either neutral or acidic, is critical to dictate the formation of 2-amino-1,3,4-thiadiazoles and 1,2,4-triazole-3-thiones from isothiocyanates and hydrazones. This is a practical protocol to achieve the chemoselectivity under mild and metal-free conditions.

Rh(III)-Catalyzed chemo-, regio- and stereoselective carboamination of sulfonyl allenes with N-phenoxy amides or N-enoxy imides

The Rh(III)-catalyzed chemo-, regio- and stereoselective carboamination of sulfonyl allenes has been realized by virtue of either N-phenoxy amides or N-enoxy imides simultaneously acting as the C- and N-sources, via redox-neutral tandem C-H activation/allene insertion/oxidative addition/C-N bond formation for the direct construction of allylamine derivatives equipped with an α-quaternary carbon center. This protocol features high atom-economy with good substrate compatibility and exhibits profound synthetic potential for late-stage C-H modification of complex molecules.

Site-selective rhodium carbene transfer of 2 hydroxy-β-nitrostyrenes with diazo compounds En route to 2-alkylated benzofurans

The Rh(iii)-catalysed cascade vinylic C–H functionalization/carbene transfer/Michael addition sequence of 2-hydroxy-β-nitrostyrenes has been realized, delivering the 2-alkylated benzofuran derivatives as potential tyrosinase inhibitors.

Specific assembly of dihydrobenzofuran frameworks via Rh(iii)-catalysed C–H coupling of N-phenoxyacetamides with 2-alkenylphenols

The synergistic dual directing group-enabled and Rh(iii)-catalysed redox-neutral C–H functionalization/[3+2] annulation has been realized for the synthesis of dihydrobenzofurans.