On December 31, 2018, Hoelzl-Hobmeier, Alena; Bauer, Andreas; Silva, Alexandre Vieira; Huber, Stefan M.; Bannwarth, Christoph; Bach, Thorsten published an article.Category: chlorides-buliding-blocks The title of the article was Catalytic deracemization of chiral allenes by sensitized excitation with visible light. And the article contained the following:
Chiral compounds exist as enantiomers that are non-superimposable mirror images of each other. Owing to the importance of enantiomerically pure chiral compounds-for example, as active pharmaceutical ingredients-separation of racemates (1:1 mixtures of enantiomers) is extensively performed. Frequently, however, only a single enantiomeric form of a chiral compound is required, which raises the question of how a racemate can be selectively converted into a single enantiomer. Such a deracemization process is entropically disfavored and cannot be performed by a conventional catalyst in solution Here we show that it is possible to photochem. deracemize chiral compounds with high enantioselectivity using irradiation with visible light (wavelength of 420 nm) in the presence of catalytic quantities (2.5 mol per cent) of a chiral sensitizer. We converted an array of 17 chiral racemic allenes into the resp. single enantiomers with 89 to 97 per cent enantiomeric excess. The sensitizer is postulated to operate by triplet energy transfer to the allene, with different energy-transfer efficiencies for the two enantiomers. It thus serves as a unidirectional catalyst that converts one enantiomer but not the other, and the decrease in entropy is compensated by light energy. Photochem. deracemization enables the direct formation of enantiopure materials from a racemic mixture of the same compound, providing a novel approach to the challenge of creating asymmetry. The experimental process involved the reaction of Methyl 6-chloro-6-oxohexanoate(cas: 35444-44-1).Category: chlorides-buliding-blocks
The Article related to catalytic enantioselective photochem transformation racemic allene visible light, Benzene, Its Derivatives, and Condensed Benzenoid Compounds: Hydrocarbons (Saturated and Unsaturated Side Chains) and other aspects.Category: chlorides-buliding-blocks
Referemce:
Chloride – Wikipedia,
Chlorides – an overview | ScienceDirect Topics