10.1002/anie.201600379
The research aims to develop a highly enantioselective method for synthesizing chiral 1,4-benzodioxanes, 1,4-benzooxazines, and chromans, which are important structural units in many bioactive natural products and drugs. The study focuses on using palladium-catalyzed alkene aryloxyarylation reactions, with key chemicals including 2-((2-methylallyl)oxy)phenol (1a), various aryl halides such as bromobenzene (2a), and chiral monophosphorus ligands like L4 and L5. The researchers optimized the reaction conditions, finding that a strong base like NaOtBu and a solvent like hexafluorobenzene (C6F6) enhanced both yield and enantioselectivity. The method demonstrated high yields (up to 90%) and excellent enantioselectivity (up to 95% ee) for a range of substrates, including those with different aryl and heteroaryl groups. The study concludes that the chiral monophosphorus ligands L4 and L5 are crucial for the high reactivity and enantioselectivity of the transformations. The findings not only provide a practical route for synthesizing these chiral compounds but also offer valuable insights into the design of better catalytic systems for similar transformations.
10.1039/c002188a
The study investigates the role of charged moieties in the aggregation of cationic conjugated polyelectrolytes (CPEs) and their application in colorimetric sensing of taurine, a sulfur-containing semiessential amino acid. The researchers utilized a cationic polythiophene derivative, poly(3-(4-methyl-30-thienyloxy)propyltrimethylammonium) (PMTPA), which is sensitive to external stimuli and can act as a colorimetric probe for detecting various bioanalytes. The study focused on the interaction between PMTPA and model analytes such as 2-naphthalenesulfonic acid (NSA), 2-naphthalenecarboxylic acid (NCA), and 2-naphthylphosphoric acid (NPA) to understand how these chemicals influence the aggregation of PMTPA. The purpose of these chemicals was to examine the hard-soft acid-base principle in the context of electrostatic interactions and to develop a method for detecting taurine. The researchers also used o-phthalaldehyde (OPA) to premodify taurine, converting it into a sulfonate-containing derivative (PI-taurine), which enhances its interaction with PMTPA and allows for colorimetric detection. The study demonstrated that PMTPA could selectively respond to taurine in aqueous solutions, leading to a color change and providing a simple means for visual detection, which has potential applications in sensing small bioanions.
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