Relative rates of alkylation for B-substituted triarylphosphines: an ortho-Boron group enhances reactivity on phosphorus.
Org Biomol Chem
; 20(31): 6183-6187, 2022 08 10.
Article
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| MEDLINE
| ID: mdl-35648392
ABSTRACT
Advancements in main-group catalysis are contingent on our ability to quantify effects that enhance reactivity in these systems. Herein we report the rates of alkylation for several substituted phosphines. We report that by incorporating a single pinacol boronic ester group in the ortho-position on triphenylphosphine, the rate of substitution with benzyl bromide is approximately 4.7 times faster than the parent compound as measured by initial rates. The corresponding meta- and para-isomers are only 1.3 and 1.5 times as fast, respectively. Using X-ray crystallographic data and quantum chemical calculations, we propose this rate acceleration occurs from an O to P electrostatic interaction that stabilizes the transition state.
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Bases de datos:
MEDLINE
Asunto principal:
Fosfinas
/
Boro
Idioma:
En
Revista:
Org Biomol Chem
Año:
2022
Tipo del documento:
Article
País de afiliación:
Estados Unidos