The Reduction of Carbonyl Compounds with Dicyclopentylzinc: A New Example of Asymmetric Amplifying Autocatalysis

Autor: Elena Sh. Saigitbatalova, Liliya Z. Latypova, Almaz A. Zagidullin, Almira R. Kurbangalieva, Ilya D. Gridnev
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: International Journal of Molecular Sciences, Vol 24, Iss 23, p 17048 (2023)
Druh dokumentu: article
ISSN: 1422-0067
1661-6596
DOI: 10.3390/ijms242317048
Popis: A previously unknown reduction of carbonyl compounds with dicyclopentylzinc is reported. Aldehydes react in mild conditions yielding corresponding primary alcohols and cyclopentene. Although cyclohexanone and acetophenone are inert to dicyclopentylzinc, a variety of heterocyclic ketones reacted readily, yielding reasonable to high yields of corresponding secondary alcohols. When the reaction was catalyzed with (–)-(1R,2S)-ephedrine, 3-acetylpyridine (10) resulted in a high yield of (S)-1-(pyridin-3-yl)ethanol (19) with >99% ee. 5-Acetyl-2-bromopyridine (11) also provided the corresponding optically active alcohol 20, albeit with a much lower optical yield. When 10% of 19 with 92% ee was used as an autocatalyst, 55% yield of the same compound was obtained, with 95% ee and 96% ee in two independent experiments. A three-stage reaction sequence starting from “no chirality” reaction yielded 19 with 6% ee. Thus, amplifying autocatalysis was detected in the reaction of ketone 10 with dicylopentylzinc.
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