Refernces
10.1007/s00706-012-0792-7
The study focuses on the asymmetric synthesis of novel chiral 1,2- and 1,3-diols through the reduction of corresponding 1,2-diketones and 1,3-diketones using an oxazaborolidine–BH3 catalyst. The research successfully synthesized seven chiral 1,2-diols and six chiral 1,3-diols, with five of the starting diketones, four racemic 1,2-diols, five chiral 1,2-diols, and two chiral 1,3-diols being identified as new compounds. The methodology applied, the oxazaborolidine–BH3 reduction, was a first-time application to these types of diketones. The study also involved the synthesis of the corresponding racemic 1,2- and 1,3-diols using NaBH4 for the determination of enantiomeric excess (ee) values through chiral resolution on high-performance liquid chromatography (HPLC) and gas chromatography (GC). The newly synthesized chiral compounds were characterized using various analytical techniques, including infrared (IR), proton and carbon-13 nuclear magnetic resonance (1H and 13C NMR), mass spectrometry (MS), and elemental analysis. The relationship between the structure of the diketone and the yield, diastereoselectivity, and enantiomeric excess was also discussed, providing insights into the stereoselective reduction process.
10.1007/s00706-012-0724-6
The research aims to develop a greener and more efficient method for the one-pot synthesis of 1,2,4,5-tetraarylated imidazoles, which are important compounds found in natural products and pharmacologically active compounds with various therapeutic properties. The study introduces the use of anhydrous FePO4 (iron(III) phosphate) as a catalyst for the four-component condensation of benzil (or benzoin), aldehydes, amines, and ammonium acetate in refluxing ethanol. The purpose of this research is to overcome the disadvantages of previous methods, such as the use of expensive reagents, longer reaction times, and the generation of toxic waste. The conclusions drawn from the study highlight the efficiency of the new method, which not only yields excellent results but also avoids the problems associated with catalyst cost, handling, safety, and pollution. The chemicals used in the process include benzil or benzoin, aromatic aldehydes, aniline, ammonium acetate, and FePO4 as the catalyst. The research demonstrates that FePO4 is an eco-friendly, reusable, recyclable, and commercially available catalyst that simplifies the isolation and purification of the products through simple washing and crystallization of the crude products.
10.1021/om100581u
The research focuses on the reactions of a bis-silylene (LSi-SiL, L = PhC(NtBu)2) and a heteroleptic chloro silylene (LSiCl) with benzil, resulting in the formation of bis(siladioxolene) and monosiladioxolene analogues with five-coordinate silicon atoms in both ring systems. The study aimed to explore the reactivity of disilyne compounds and their potential to form stable siladioxolene derivatives, which are electronically stabilized by σ-donor ligands. The key findings were that the central Si-Si bond in the bis(siladioxolene) derivative was not cleaved during the reaction, and the formal oxidation state of silicon in the products was +3 and +4, respectively. The chemicals used in the process included LSi-SiL (4), LSiCl (6), benzil, toluene, and other reagents for characterization such as NMR spectroscopy, EI-MS spectrometry, and elemental analysis. The research concluded that siladioxolenes can be electronically stabilized by σ-donor ligands, and the reactions proceeded via a [1+4] cycloaddition mechanism, yielding stable compounds with five-coordinate silicon atoms.
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