Abstract:

To better integrate cutting-edge knowledge, theories, technologies, and methods into senior undergraduate comprehensive experimental courses, this paper designed an experiment involving the modification of diacetone-D-galactose based on Dess-Martin (DMP) oxidation and Horner-Wadsworth-Emmons (HWE) reactions. We established experimental procedures by researching the oxidation of alcohols and the alkenylation of aldehydes. 2-iodoacylbenzoic acid (IBX) was synthesized by oxidizing o-iodobenzoic acid with potassium peroxymonosulfate (oxone). This was then transformed into DMP under the influence of acetic acid and acetic anhydride. DMP was subsequently employed to oxidize diacetone-D-galactose, and the HWE reaction was finally used to achieve the differential isomeric aldehyde alkenylation. The progress of the reaction was monitored using thin-layer chromatography (TLC) with various staining methods. Schlenk technique was adopted for anhydrous and anaerobic operations, and the target products were isolated and purified through column chromatography. The structure and purity of the compounds were characterized using infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-resolution mass spectrometry. DMP oxidation has the advantages of mild conditions, simple operations, high yield and selectivity, and low toxicity. The designed experimental procedures are comprehensive, rich in content, and emphasizes integrative nature, which is beneficial for the organic integration of students' knowledge, capabilities, and qualities, while cultivating their ability to tackle complex problems and develop advanced thinking skills.

Key words: Dess-Martin oxidation, Horner-Wadsworth-Emmons reaction, Diacetone-D-galactose, Schlenk technology, Column chromatography