Competing Mechanisms in Palladium-Catalyzed Alkoxycarbonylation of Styrene
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F24%3A00585169" target="_blank" >RIV/61388963:_____/24:00585169 - isvavai.cz</a>
Alternative codes found
RIV/00216208:11310/24:10483701
Result on the web
<a href="https://doi.org/10.1021/acscatal.4c00966" target="_blank" >https://doi.org/10.1021/acscatal.4c00966</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acscatal.4c00966" target="_blank" >10.1021/acscatal.4c00966</a>
Alternative languages
Result language
angličtina
Original language name
Competing Mechanisms in Palladium-Catalyzed Alkoxycarbonylation of Styrene
Original language description
Palladium-catalyzed carbonylation is a versatile method for the synthesis of various aldehydes, esters, lactones, or lactams. Alkoxycarbonylation of alkenes with carbon monoxide and alcohol produces either saturated or unsaturated esters as a result of two distinct catalytic cycles. The existing literature presents an inconsistent account of the procedures favoring oxidative carbonylation products. In this study, we have monitored the intermediates featured in both catalytic cycles of the methoxycarbonylation of styrene PhCH & boxH, CH2 as a model substrate, including all short-lived intermediates, using mass spectrometry. Comparing the reaction kinetics of the intermediates in both cycles in the same reaction mixture shows that the reaction proceeding via alkoxy intermediate [Pd-II]-OR, which gives rise to the unsaturated product PhCH & boxH, CHCO2Me, is faster. However, with an advancing reaction time, the gradually changing reaction conditions begin to favor the catalytic cycle dominated by palladium hydride [Pd-II]-H and alkyl intermediates, affording the saturated products PhCH2CH2CO2Me and PhCH(CO2Me)CH3 preferentially. The role of the oxidant proved to be crucial: using p-benzoquinone results in a gradual decrease of the pH during the reaction, swaying the system from oxidative conditions toward the palladium hydride cycle. By contrast, copper(II) acetate as an oxidant guards the pH within the 5-7 range and facilitates the formation of the alkoxy palladium complex [Pd-II]-OR, which favors the oxidative reaction producing PhCH & boxH,CHCO2Me with high selectivity. Hence, it is the oxidant, rather than the catalyst, that controls the reaction outcome by a mechanistic switch. Unraveling these principles broadens the scope for developing alkoxycarbonylation reactions and their application in organic synthesis.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10401 - Organic chemistry
Result continuities
Project
—
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
ACS Catalysis
ISSN
2155-5435
e-ISSN
2155-5435
Volume of the periodical
14
Issue of the periodical within the volume
8
Country of publishing house
US - UNITED STATES
Number of pages
10
Pages from-to
5710-5719
UT code for WoS article
001194996300001
EID of the result in the Scopus database
2-s2.0-85189558674