Chiroptical studies

Barrett, M.W. et al.. Plant proanthocyanidins. Part 6. Chiroptical studies. Part 95. Circular dichroism of procyanidins, J. Chem. Soc., Perkin Trans. 1, 2375, 1979. 

As shown in this section, CD spectroscopy has the potential to provide reliable configurational assignments for many products of stereoselective synthesis, requiring only small amounts of material (usually 1 mg or less) and simple analytical procedure. In addition, many nonchro-mophoric functional groups (c.g. amino, hydroxy groups) can be converted to chromophoric derivatives suitable for chiroptical studies. 

From another shallow-water variety of L majuscula found in Hawaii, a new crystalline metabolite pukeleimide C (102) was isolated. The structure was secured by X-ray studies [163]. Chiroptical studies showed the compound to be racemic and, probably, an artefact. A separate collection of the cyanophyte did not contain pukeleimide C but, instead, yielded a group of related metabolites, e.g. 103, whose structures were assigned from spectral data [164], Unfortunately, no information is available on the bioactivity of these metabolites. 

Studies on the chirality of dendritic molecules 4.2.2.1 Chiroptical studies... 

Chiroptical studies on dendrimers with chiral cores... 

Enantiomeric resolution of the corresponding racemates was accomplished by HPLC on chiral stationary phases (CSP) [23]. Chiroptical studies by means of circular dichroism indicated that the chiral dendrimer core exerted some influence... 

Chiroptical studies of molecules in electronically excited states... 

Support for a helical structure of polyketones arose from chiroptical studies as a function of temperature in the glassy state.246... 

In 1990, Brunner [5], McKervey [6], and Ikegami [7] and their respective coworkers independently introduced chiral rhodium(II) carboxylates for asymmetric diazocarbonyl transformations. At that time the only chiral rhodium(II) carboxylates known were those derived from (R) and (S)-mandelic acid which had been prepared by Cotton and co-workers [8] for structural and chiroptical studies. Enantiopure carboxylates (1) on a dirhodium core (substituents varied from H, Me, and Ph to OH, NHAc, and CFj) were assessed by Brunner [5] for enantioselective cyclopropanation of alkenes with ethyl diazoacetate. McKervey... 

Chiroptical studies have been reported for a variety of sulphinyl and sulphinate derivatives of steroids, " and also for steroid N-acetylglucosaminides. ... 

Details of the Czech group s chiroptical studies of the Iboga and Voacanga alkaloids, summarized previously, " have now been published. ... 

Ab initio calculations have been performed for (lithioalkyl)phosphonates and, together with NMR and chiroptical studies, for methyl methylphosphono-fluoridate. 2 Finally, steric and stereoelectronic effects in 1,3,2-dioxaphosphor-inanes have been discussed. 

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