Corrigendum to: Biomass-Derived Reaction Media Towards the Iodination of Anilines Under the Catalytic Influence of Magnetically Separable Pd@rGO-CuFe ₂ O ₄

The publisher regrets that typographical errors appeared in the published version of the above article. Also, in the published version of this article [1], the reference section includes references 41(a-e), whereas the in-text citations extend to 41(g). To ensure clarity and accuracy of the published content, this section has been revised. The original article can be found online at: https://www.eurekaselect.com/article/151054 Details of the error and its correction are provided below. Original: Thus, the development of a method that addresses challenges such as the use of expensive and harmful reagents, limitations in substrate scope, and formation of side products, is highly desirable. In this regard, our research group has been actively involved in developing cost-effective and environmentally friendly methods for the preparation of essential compounds [36-40]. The intriguing applications of nanocomposites in various research fields have remained our inspiration [41a-f]. The immobilization of palladium on rGO-MNPs (i.e., Pd@rGO-CuFe2O4) was previously attempted by our group and has been proven to be a potential catalyst in crucial organic transformations [41a, b]. Considering the drawbacks associated with current synthetic routes for the iodination of anilines, we report an economical and green method using the magnetically separable catalyst rGOMNPs (i.e., Pd@rGO-CuFe2O4) and a biomass-derived solvent, GVL, under mild reaction conditions. Having noticed the influences and the optimum amounts required for molecular iodine and the catalyst, further studies were carried out using 1.1 equiv. of molecular iodine and 2 mg of the catalyst (Table 1, entries 6-9, 14). Considering the importance of the reaction medium for this transformation, we then attempted to explore the scope of solvents. In this regard, it was found that the use of GVL as a biomass-derived reaction medium for this transformation led to the isolation of product 2a in 91% yield, with the identification of products 2a and 3a in a 99:1 ratio (Table 1, entry 6). Replacement of GVL with traditional solvents like methanol, ethanol, and iso-propanol delivered the corresponding product 2a in 75%, 73%, and 70% yields, respectively (Table 1, entries 7-9), with noticeably lower selectivity. These results encouraged us to employ GVL as an important and suitable biomass-derived reaction medium for this transformation. GVL is a polar aprotic solvent that dissolves aniline well without displaying strong hydrogen bonding to it, preserving its reactivity. GVL has been proven to stabilize the proposed transition states and reaction intermediates better than solvents like water due to its polarity and dielectric constant [41g]. This stabilization lowers the activation energy, making the iodination faster and more selective. Next, the influences of surrogate oxidants such as TBHP (Table 1, entry 10), K2S2O8 (Table 1, entry 11), (NH4)2S2O8 (Table 1, entry 12), and di-tertbutyl peroxide (DTBP) (Table 1, entry 13) were investigated. These experiments highlighted the efficacy of the catalyst to drive the reaction towards higher yields and selectivity for the para-iodinated anilines (Table 1, entry 6). At an elevated temperature (80 °C), the selectivity towards 2a decreased, whereas the selectivity towards the diiodo-derivative 3a increased drastically (2a:3a = 20:80). As the thermodynamically controlled product (TCP), the yield of 3a reached as high as 55% (Table 1, entry 14). The increase in temperature enhanced the formation of 3a, validating the high energy requirement for this product. The elevated temperature likely fulfills the energy needed for the formation of the sterically challenging product 3a, manifesting it as the thermodynamically controlled product (TCP). Finally, to examine the role of Pd@rGO-CuFe2O4 as a catalyst, a reaction was conducted under Pd@rGO-CuFe2O4-free conditions. This experiment led to unsatisfactory results, with only 10% yield of the corresponding product 2a and the formation of several unidentified products in the reaction mixture, highlighting the necessity of Pd@rGO-CuFe2O4 as a novel heterogeneous catalyst for the formation of iodinated anilines. We also assume that the absence of Pd@rGO-CuFe2O4 leads to incomplete oxidation of molecular iodine, resulting in the formation of unidentified side products. With the aim of selectively preparing the 4-iodoaniline derivatives 2 (the corresponding kinetically controlled product (KCP)), screening of reaction conditions revealed that the use of aniline (1a) with 1.1 equiv. of molecular iodine and 2 mg of Pd@rGO-CuFe2O4 in GVL (1.5 mL) as a biomass-derived solvent at 25 °C is the optimal process (Table 1, entry 6). Revised: Thus, the development of a method that addresses challenges, such as the use of expensive and harmful reagents, limited substrate scope, and the formation of side products, is highly desirable. In this regard, our research group has been actively involved in developing cost-effective, environmentally friendly methods for the preparation of essential compounds [36-40]. The intriguing applications of nanocomposites in various research fields have remained our inspiration [41a-e]. The immobilization of palladium on rGO-MNPs (i.e., Pd@rGO-CuFe2O4) was previously attempted by our group and has proven to be a potential catalyst in crucial organic transformations [41a, b]. Given the drawbacks of current synthetic routes for iodinating anilines, this study reports an economical, green method using the magnetically separable catalyst rGOMNPs (i.e., Pd@rGO-CuFe2O4) and a biomass-derived solvent, GVL, under mild reaction conditions. Having noted the influences and optimal amounts of molecular iodine and the catalyst, further studies were carried out using 1.1 equiv. of molecular iodine and 2 mg of the catalyst (Table 1, entries 6-9, 14). Considering the importance of the reaction medium for this transformation, this study then attempted to explore the scope of solvents. In this regard, it was found that using GVL as a biomass-derived reaction medium for this transformation led to the isolation of product 2a in 91% yield, with the identification of products 2a and 3a in a 99:1 ratio (Table 1, entry 6). Replacement of GVL with traditional solvents, such as methanol, ethanol, and isopropanol, delivered the corresponding product 2a in 75%, 73%, and 70% yields, respectively (Table 1, entries 7-9), with noticeably lower selectivity. These results encouraged this study to employ GVL as an important and suitable biomass-derived reaction medium for this transformation. GVL is a polar aprotic solvent that dissolves aniline well without forming strong hydrogen bonds, thereby preserving its reactivity. GVL has been shown to stabilize the proposed transition states and reaction intermediates more effectively than solvents, such as water, due to its polarity and dielectric constant. This stabilization lowers the activation energy, making the iodination faster and more selective. Next, the influence of surrogate oxidants, such as TBHP (Table 1, entry 10), K2S2O8 (Table 1, entry 11), (NH4)2S2O8 (Table 1, entry 12), and di-tertbutyl peroxide (DTBP) (Table 1, entry 13), was investigated. These experiments highlighted the efficacy of the catalyst in driving the reaction towards higher yields and selectivity for para-iodinated anilines (Table 1, entry 6). At an elevated temperature (80 °C), the selectivity towards 2a decreased, whereas the selectivity towards the diiodo-derivative 3a increased drastically (2a:3a = 20:80). As the thermodynamically controlled product (TCP), the yield of 3a reached as high as 55% (Table 1, entry 14). The increase in temperature enhanced the formation of 3a, validating the high energy requirement for this product. The elevated temperature likely provides the energy required for the formation of the sterically challenging product 3a, making it the thermodynamically controlled product (TCP). Finally, to examine the role of Pd@rGO-CuFe2O4 as a catalyst, a reaction was conducted under Pd@rGO-CuFe2O4-free conditions. This experiment yielded unsatisfactory results, with only 10% yield of the corresponding product 2a and the formation of several unidentified products in the reaction mixture, highlighting the need for Pd@rGOCuFe2O4 as a novel heterogeneous catalyst for the synthesis of iodinated anilines. We also assume that the absence of Pd@rGO-CuFe2O4 leads to incomplete oxidation of molecular iodine, resulting in the formation of unidentified side products. To selectively prepare the 4-iodoaniline derivatives 2 (the corresponding kinetically controlled product (KCP)), screening of reaction conditions revealed that the use of aniline (1a) with 1.1 equiv. of molecular iodine and 2 mg of Pd@rGO-CuFe2O4 in GVL (1.5 mL) as a biomass-derived solvent at 25 °C is the optimal process (Table 1, entry 6).