WebNovel chiral crown ethers, which contain pinacol or biphenyl residues exerting steric effect, were synthesized from L-(+)-tartaric acid or D-(—)-mannitol as chiral sources, and the stability constants and chiral recognitions of these crown ethers were measured by use of t-butylammonium thiocyanate and (±)-phenylethylamine respectively. WebJan 1, 2014 · ethers, e.g., crown ether diesters, a zacrown ethers, thiacrown ethers, and chiral crown ethers, have b een documented in the literature and their binding pr operties such as binding selectivity ...
Synthesis of chiral crown ethers derived from - ScienceDirect
WebWe report on a combined experimental and computational study of the chiral recognition of the amino acid serine in protonated form (l/d-SerH+), by the crown ether (all-S)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (S-18c6H4). Infrared and vibrational circular dichroism spectroscopies (IR-VCD) are employed to characterize the chiroptical response of the … WebMay 1, 2024 · Cram et al. reported the first example of chiral crown ether-catalyzed Michael addition reactions (Scheme 1) [44].Two chiral BINOL-based crown ethers (1 … how do we see objects that only receive light
Chiroptical property of TPE triangular macrocycle crown ethers …
WebMay 16, 2014 · We report on the synthesis of a new, supported phase transfer catalyst and its asymmetric induction. An inorganic-polymer-supported chiral crown ether was prepared by the reaction between an optically active macrocycle deriving from methyl-α-d-glucopyranoside and silica nanofibres. The inorganic carrier of the catalyst has high … WebCram found that chiral crown ethers in the presence of alkali metal bases catalyzed the asymmetric Michael addition [46]. Ketoester 6 underwent addition to 7 in more than 99% … WebCram found that chiral crown ethers in the presence of alkali metal bases catalyzed the asymmetric Michael addition [46]. Ketoester 6 underwent addition to 7 in more than 99% ee in the presence of (S,S)-49 and KOf-Bu (4 mol %). … ph of crystal springs water