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

Result code in 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>

Result on the web

<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>

Result language

angličtina

Original language name

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

Original language description

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.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10401 - Organic chemistry

Project

<a href="/en/project/GJ19-20467Y" target="_blank" >GJ19-20467Y: Light-Controlled Reversible Formation of Charge-Separated States</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

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

Name of the periodical

Journal of the American Chemical Society

ISSN

0002-7863

e-ISSN

—

Volume of the periodical

142

Issue of the periodical within the volume

25

Country of publishing house

US - UNITED STATES

Number of pages

13

Pages from-to

10942-10954

UT code for WoS article

000543780500011

EID of the result in the Scopus database

2-s2.0-85087034116