Impact of Excited-State Antiaromaticity Relief in a Fundamental Benzene Photoreaction Leading to Substituted Bicyclo[3.1.0]hexenes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F20%3A00524765" target="_blank" >RIV/61388963:_____/20:00524765 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.acs.org/doi/10.1021/jacs.9b13769" target="_blank" >https://pubs.acs.org/doi/10.1021/jacs.9b13769</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/jacs.9b13769" target="_blank" >10.1021/jacs.9b13769</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Impact of Excited-State Antiaromaticity Relief in a Fundamental Benzene Photoreaction Leading to Substituted Bicyclo[3.1.0]hexenes

Popis výsledku v původním jazyce

Benzene exhibits a rich photochemistry which can provide access to complex molecular scaffolds difficult to access with reactions in the electronic ground state. While benzene is aromatic in its ground state it is antiaromatic in its lowest ππ* excited states. Herein, we clarify to what extent relief of excited state antiaromaticity (ESAA) triggers a fundamental benzene photoreaction: the photoinitiated nucleophilic addition of solvent to benzene in acidic media leading to substituted bicyclo[3.1.0]hex-2-enes. The reaction scope was probed experimentally and it was found that silyl substituted benzenes provide the most rapid access to bicyclo[3.1.0]hexene derivatives, formed as single isomers with three stereogenic centers in yields up to 75% in one step. Two major mechanism hypotheses, both involving ESAA relief, were explored through quantum chemical calculations and experiments. The first mechanism involves protonation of excited state benzene and subsequent rearrangement to bicyclo[3.1.0]hexenium cation, trapped by a nucleophile, while the second involves photorearrangement of benzene to benzvalene followed by protonation and nucleophilic addition. Our studies reveal that the second mechanism is operative. We also clarify that similar ESAA relief leads to puckering of S1 state silabenzene and pyridinium ion, where the photorearrangement of the latter is of established synthetic utility. Finally, we identified causes for the limitations of the reaction, information that should be valuable in explorations of similar photoreactions. Taken together, we reveal how the ESAA in benzene and 6π-electron heterocycles trigger photochemical distortions that provide access to complex three-dimensional molecular scaffolds from simple reactants.

Název v anglickém jazyce

Impact of Excited-State Antiaromaticity Relief in a Fundamental Benzene Photoreaction Leading to Substituted Bicyclo[3.1.0]hexenes

Popis výsledku anglicky

Benzene exhibits a rich photochemistry which can provide access to complex molecular scaffolds difficult to access with reactions in the electronic ground state. While benzene is aromatic in its ground state it is antiaromatic in its lowest ππ* excited states. Herein, we clarify to what extent relief of excited state antiaromaticity (ESAA) triggers a fundamental benzene photoreaction: the photoinitiated nucleophilic addition of solvent to benzene in acidic media leading to substituted bicyclo[3.1.0]hex-2-enes. The reaction scope was probed experimentally and it was found that silyl substituted benzenes provide the most rapid access to bicyclo[3.1.0]hexene derivatives, formed as single isomers with three stereogenic centers in yields up to 75% in one step. Two major mechanism hypotheses, both involving ESAA relief, were explored through quantum chemical calculations and experiments. The first mechanism involves protonation of excited state benzene and subsequent rearrangement to bicyclo[3.1.0]hexenium cation, trapped by a nucleophile, while the second involves photorearrangement of benzene to benzvalene followed by protonation and nucleophilic addition. Our studies reveal that the second mechanism is operative. We also clarify that similar ESAA relief leads to puckering of S1 state silabenzene and pyridinium ion, where the photorearrangement of the latter is of established synthetic utility. Finally, we identified causes for the limitations of the reaction, information that should be valuable in explorations of similar photoreactions. Taken together, we reveal how the ESAA in benzene and 6π-electron heterocycles trigger photochemical distortions that provide access to complex three-dimensional molecular scaffolds from simple reactants.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10401 - Organic chemistry

Projekt

<a href="/cs/project/GJ19-20467Y" target="_blank" >GJ19-20467Y: Světlem řízené systémy pro reversibilní separaci nábojů</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

Journal of the American Chemical Society

ISSN

0002-7863

e-ISSN

—

Svazek periodika

142

Číslo periodika v rámci svazku

25

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

13

Strana od-do

10942-10954

Kód UT WoS článku

000543780500011

EID výsledku v databázi Scopus

2-s2.0-85087034116