Chiral ethylene-bridged flavinium salts: The stereoselectivity of flavin-10a-hydroperoxide formation and the effect of substitution on the photochemical properties

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F17%3A43914941" target="_blank" >RIV/60461373:22310/17:43914941 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/60461373:22810/17:43914941

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.tetasy.2017.10.029" target="_blank" >http://dx.doi.org/10.1016/j.tetasy.2017.10.029</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.tetasy.2017.10.029" target="_blank" >10.1016/j.tetasy.2017.10.029</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Chiral ethylene-bridged flavinium salts: The stereoselectivity of flavin-10a-hydroperoxide formation and the effect of substitution on the photochemical properties

Popis výsledku v původním jazyce

series of chiral non-racemic N1,N10-ethylene bridged flavinium salts 4 was prepared using enantiomerically pure 2-substituted 2-aminoethanols (R = isopropyl, phenyl, benzyl, 4-methoxybenzyl, 4-benzyloxybenzyl) derived from amino acids as the sole source of chirality. The flavinium salts were shown to form 10a-hydroperoxy- and 10a-methoxy-adducts with moderate to high diastereoselectivity depending on the ethylene bridge substituent originating from the starting amino acid. High diastereoselectivities (dr values from 80:20 to &gt;95:5) were observed for flavinium salts bearing benzyl substituents attached to the ethylene bridge. The benzyl group preferred the face-to-face (syn) orientation relative to the flavinium unit; thereby effectively preventing nucleophilic attack from one side. This conformation was found to be the most stable according to DFT calculations. Consequently, the presence of benzyl groups causes intermolecular fluorescence quenching resulting in a significant decrease in the fluorescence quantum yield from 11% for 4a bearing an isopropyl substituent to 0.3% for 4c containing a benzyl group and to a value lower than 0.1% for the benzyloxybenzyl derivative 4e.

Název v anglickém jazyce

Chiral ethylene-bridged flavinium salts: The stereoselectivity of flavin-10a-hydroperoxide formation and the effect of substitution on the photochemical properties

Popis výsledku anglicky

series of chiral non-racemic N1,N10-ethylene bridged flavinium salts 4 was prepared using enantiomerically pure 2-substituted 2-aminoethanols (R = isopropyl, phenyl, benzyl, 4-methoxybenzyl, 4-benzyloxybenzyl) derived from amino acids as the sole source of chirality. The flavinium salts were shown to form 10a-hydroperoxy- and 10a-methoxy-adducts with moderate to high diastereoselectivity depending on the ethylene bridge substituent originating from the starting amino acid. High diastereoselectivities (dr values from 80:20 to &gt;95:5) were observed for flavinium salts bearing benzyl substituents attached to the ethylene bridge. The benzyl group preferred the face-to-face (syn) orientation relative to the flavinium unit; thereby effectively preventing nucleophilic attack from one side. This conformation was found to be the most stable according to DFT calculations. Consequently, the presence of benzyl groups causes intermolecular fluorescence quenching resulting in a significant decrease in the fluorescence quantum yield from 11% for 4a bearing an isopropyl substituent to 0.3% for 4c containing a benzyl group and to a value lower than 0.1% for the benzyloxybenzyl derivative 4e.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

10401 - Organic chemistry

Projekt

<a href="/cs/project/GA16-09436S" target="_blank" >GA16-09436S: Fotokatalytická a organokatalytická Mitsunobuova reakce s využitím derivátů flavinů a viditelného světla</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Tetrahedron Asymmetry

ISSN

0957-4166

e-ISSN

—

Svazek periodika

28

Číslo periodika v rámci svazku

12

Stát vydavatele periodika

IE - Irsko

Počet stran výsledku

11

Strana od-do

1780-1791

Kód UT WoS článku

000418988400014

EID výsledku v databázi Scopus

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