Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• nitrite as a nitrogen-oxygen source, and solely using aluminum trichloride as the additive. This approach circumvents the need for costly or highly toxic transition metals and presents a novel pathway for the synthesis of isoxazole derivatives. Keywords: aluminum trichloride; Lewis acid; isoxazole

• that the reaction is not a free radical reaction. Based on the control experiments and previous literature [21], we propose the following possible mechanism, which is shown in Scheme 5. Aluminum trichloride reacts with sodium nitrite to form an intermediate aluminum complex A, which is further

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• was heated, in which case decomposition took place (Table 1, entry 15). Solutions of 15a in dichloromethane also decomposed rapidly when treated with aluminum trichloride or boron trifluoride at 50 °C, although no reaction was apparent at room temperature even after 18 hours (Table 1, entries 16–19

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• a few examples of FCRs employing manual grinding: reserpine acylation with AlCl3 [6] and acylation reaction of aromatics [7]. One of the reasons for this scarcity is the hygroscopic nature of the aluminum trichloride catalyst [8][9][10][11][12] when exposed to air humidity. This problem could be