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Highly active polymeric organocatalyst: Chiral ionic polymers prepared from 10,11‐didehydrogenated cinchonidinium salt

“…We prepared 10,11‐didehydrogenated cinchonidine 3 from cinchonidine 1 through brominated intermediate 2 according to Hoffmann's procedure (Fig. ) . The quinuclidine nitrogen of 3 was then benzylated with benzyl bromide to give 10,11‐didehydrogenated cinchonidinium salt 4 (Fig.…”

“…The thiol‐ene reaction was also applied to immobilize cinchona alkaloid catalysts on a polymer support . Contrary to the sp 2 to sp 3 transformation of the carbon atom of the 3‐vinyl group, sp carbon formation is also possible to prepare 3‐ethynyl derivatives; for example, 10,11‐didehydrogenated (3‐ethynyl) cinchonidine was readily prepared from cinchonidine by a bromination–dehydrobromination reaction . The introduction of the 3‐ethynyl group onto cinchona‐based organocatalysts should affect the catalytic activity because of the differences between the vinyl and ethynyl groups.…”

Alkaloids and Isoprenoids Modification by Copper(I)-Catalyzed Huisgen 1,3-Dipolar Cycloaddition (Click Chemistry): Toward New Functions and Molecular Architectures

“…This class of alkaloids is ideally suited for the CuAAC reaction because of an easy installation of the desired alkyne and azide functionality. For example, 10,11-didehydro Cinchona alkaloids 5 – 8 bearing a terminal acetylene group can be prepared by the bromination of the vinyl double bond followed by subsequent double elimination as described by Hoffmann et al or by optimized chromatography-free large-scale protocol reported by Kacprzak (Scheme ). Due to the remote position of the alkyne group and the 1,2-aminoalcohol domain responsible for the molecular recognition or catalytic function, the resulting 10,11-didehydro Cinchona alkaloids appears to be ideally suited for the CuAAC-triggered immobilization.…”

Photoelectron Spectra and Electronic Structure of Some Diastereomeric Quinuclidine Derivatives

“…Because of the p-anisotropy of the vinyl group and increased twisting of the cage, a corresponding through-bond interaction in 3 and 4 is less favourable although the interacting p(CC)orbital has a lower energy than p(C C). Apparently, the enhanced polarity in 5 and 6 and in the synthetic 10,11-didehydro Cinchona alkaloids [24] is a consequence of these structural and electronic changes (Scheme 5). The electronic properties of the 1,2-amino alcohol functionality in 1 ± 6 are modified by the electronic properties of the C5 substituent and by its steric demand.…”