A mild, cascade type methodology was developed for the synthesis of polyphenolic ethers by the palladium-catalyzed cross coupling of phenols and halo compounds under microwave heating. In most cases, reactions run in ...A mild, cascade type methodology was developed for the synthesis of polyphenolic ethers by the palladium-catalyzed cross coupling of phenols and halo compounds under microwave heating. In most cases, reactions run in neat conditions and in some cases, IPA/water mixture, and 1,4-dioxane were employed as solvents to furnish the products. By applying this new method, we were able to synthesize and purify a good number of polyether compounds with complete spectral data.展开更多
Phenolic compounds present in medicinal and edible plants such as flavonoids, chalcones, coumarins, quinones, and phenolic acids. The antioxidant potential of phenolic compounds shows potent activities for cancer prev...Phenolic compounds present in medicinal and edible plants such as flavonoids, chalcones, coumarins, quinones, and phenolic acids. The antioxidant potential of phenolic compounds shows potent activities for cancer prevention and its treatment. From a green chemistry point of view, cascade (tandem) reactions are ideal techniques in organic synthesis for building complex structures. Cascade techniques are sometimes observed in coupling reactions under mild conditions with a tolerance of multifunctional groups. It will be interesting to find a cascade type reaction to synthesize polyphenolic ethers. This research project achieves a new cross-coupling method for establishing polyphenolic ethers from mixed phenols and halides in the presence of palladium catalyst in moderate to good yields.展开更多
The Palladium inserted hydridopalladium species represents as RCOOPdH. This work finds an interesting coupling of palladium inserted RCOOPdH species with potassium styryltrifluoroborates to synthesize new kinds of sty...The Palladium inserted hydridopalladium species represents as RCOOPdH. This work finds an interesting coupling of palladium inserted RCOOPdH species with potassium styryltrifluoroborates to synthesize new kinds of styryl ester compounds. Pd(OAc)<sub>2</sub> was most effective catalyst for this new cross-coupling reaction under microwave irradiation and gave styryl esters in good to moderate yields.展开更多
An interesting regioselectivity is observed when the mixture of potassium crotyltrifluoroborate (1a) and aroyl chlorides having electron-deficient and electron-rich groups is microwaved in the presence of palladium-ca...An interesting regioselectivity is observed when the mixture of potassium crotyltrifluoroborate (1a) and aroyl chlorides having electron-deficient and electron-rich groups is microwaved in the presence of palladium-catalyst. In the case of electron withdrawing group with phenyl ring of aroyl chlorides, isomerized α,β-unsaturated compound 3 is the product whereas electron donating group with phenyl ring of aroyl chlorides furnishes α-adduct 4. Similar aroylation reaction is also established for potassium allyltrifluoroborate (1b). In this case, regioselectivity is unaffected with changing electron-rich or electron-deficient groups in phenyl ring of the aroyl chlorides. Reactions proceed with, essentially in same rate, affording the corresponding aryl propenyl ketones (crotonophenones) 5 in good to high yields.展开更多
Anhydrous Cu(OAc)<sub>2</sub> mediated efficient protocol has been developed in the area of C-O coupling from potassium aryltrifluoroborates and aliphatic amino alcohols such as β-hydroxy, γ-hydroxy, and...Anhydrous Cu(OAc)<sub>2</sub> mediated efficient protocol has been developed in the area of C-O coupling from potassium aryltrifluoroborates and aliphatic amino alcohols such as β-hydroxy, γ-hydroxy, and δ-hydroxy amines. The scope of this transformation focuses on direct O-arylation and O-styrylation. The reaction vial loaded with reactants under argon atmosphere is microwaved at 140°C for 30 min to furnish the corresponding cross-coupling product, amino ethers, in good yields.展开更多
文摘A mild, cascade type methodology was developed for the synthesis of polyphenolic ethers by the palladium-catalyzed cross coupling of phenols and halo compounds under microwave heating. In most cases, reactions run in neat conditions and in some cases, IPA/water mixture, and 1,4-dioxane were employed as solvents to furnish the products. By applying this new method, we were able to synthesize and purify a good number of polyether compounds with complete spectral data.
文摘Phenolic compounds present in medicinal and edible plants such as flavonoids, chalcones, coumarins, quinones, and phenolic acids. The antioxidant potential of phenolic compounds shows potent activities for cancer prevention and its treatment. From a green chemistry point of view, cascade (tandem) reactions are ideal techniques in organic synthesis for building complex structures. Cascade techniques are sometimes observed in coupling reactions under mild conditions with a tolerance of multifunctional groups. It will be interesting to find a cascade type reaction to synthesize polyphenolic ethers. This research project achieves a new cross-coupling method for establishing polyphenolic ethers from mixed phenols and halides in the presence of palladium catalyst in moderate to good yields.
文摘The Palladium inserted hydridopalladium species represents as RCOOPdH. This work finds an interesting coupling of palladium inserted RCOOPdH species with potassium styryltrifluoroborates to synthesize new kinds of styryl ester compounds. Pd(OAc)<sub>2</sub> was most effective catalyst for this new cross-coupling reaction under microwave irradiation and gave styryl esters in good to moderate yields.
文摘An interesting regioselectivity is observed when the mixture of potassium crotyltrifluoroborate (1a) and aroyl chlorides having electron-deficient and electron-rich groups is microwaved in the presence of palladium-catalyst. In the case of electron withdrawing group with phenyl ring of aroyl chlorides, isomerized α,β-unsaturated compound 3 is the product whereas electron donating group with phenyl ring of aroyl chlorides furnishes α-adduct 4. Similar aroylation reaction is also established for potassium allyltrifluoroborate (1b). In this case, regioselectivity is unaffected with changing electron-rich or electron-deficient groups in phenyl ring of the aroyl chlorides. Reactions proceed with, essentially in same rate, affording the corresponding aryl propenyl ketones (crotonophenones) 5 in good to high yields.
文摘Anhydrous Cu(OAc)<sub>2</sub> mediated efficient protocol has been developed in the area of C-O coupling from potassium aryltrifluoroborates and aliphatic amino alcohols such as β-hydroxy, γ-hydroxy, and δ-hydroxy amines. The scope of this transformation focuses on direct O-arylation and O-styrylation. The reaction vial loaded with reactants under argon atmosphere is microwaved at 140°C for 30 min to furnish the corresponding cross-coupling product, amino ethers, in good yields.
