Determination of the pKa Value of a Brønsted Acid by 19F NMR Spectroscopy DOI Creative Commons

Emily F. Griffiths,

J. H. Dixon,

Andrew J. M. Caffyn

et al.

Magnetic Resonance in Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 16, 2024

ABSTRACT Brønsted acids, such as phosphoric acids derived from chiral 1,1′‐bi‐2‐naphthol (BINOL), are important catalysts in the formation of carbon–carbon and carbon–heteroatom bonds, for example. The catalytic activity these is strongly linked to their acidity, such, evaluation compounds determine pK a values provides insight into activity. Herein, 19 F{ 1 H} NMR methodology detailed fluorinated binaphthyl‐derived phosphinic acid, rac‐ , acetonitrile presence sulfonamide reference compound ( 2 – 4 ). approach was tested initially using 3 with Δ (0.08) strong agreement previously reported (6.6 6.68/6.73 Sigmoidal curves normalised chemical shift change (Δδ) against equivalents base phosphazene P ‐ t Bu added overlapped but case rac either or there significant separation. A variety different approaches determining were compared. Values determined when Δδ 90% optimal whereas 75% resulting being be 8.47–8.71.

Language: Английский

Oxidative Scission of Bicyclo[2.2.2]octenones: Untying the α-Dimethoxycarbonyl DOI Creative Commons
Tsung‐Chieh Yao, Yu–Chee Tseng,

J. Y. Li

et al.

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

This study explores the selective oxidative scission of bicyclo[2.2.2]octenones derived from masked o-benzoquinones (MOBs). By employing fragmentation ketoximes and Schmidt-type reactions, we achieved cleavage α-dimethoxy carbonyl groups to yield highly functionalized cyclohexene frameworks, showcasing expanding synthetic utility in complex organic synthesis. The methodologies developed are anticipated contribute advancements pharmaceutical chemistry.

Language: Английский

Citations

0
Determination of the pKa Value of a Brønsted Acid by 19F NMR Spectroscopy DOI Creative Commons

Emily F. Griffiths,

J. H. Dixon,

Andrew J. M. Caffyn

et al.

Magnetic Resonance in Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 16, 2024

ABSTRACT Brønsted acids, such as phosphoric acids derived from chiral 1,1′‐bi‐2‐naphthol (BINOL), are important catalysts in the formation of carbon–carbon and carbon–heteroatom bonds, for example. The catalytic activity these is strongly linked to their acidity, such, evaluation compounds determine pK a values provides insight into activity. Herein, 19 F{ 1 H} NMR methodology detailed fluorinated binaphthyl‐derived phosphinic acid, rac‐ , acetonitrile presence sulfonamide reference compound ( 2 – 4 ). approach was tested initially using 3 with Δ (0.08) strong agreement previously reported (6.6 6.68/6.73 Sigmoidal curves normalised chemical shift change (Δδ) against equivalents base phosphazene P ‐ t Bu added overlapped but case rac either or there significant separation. A variety different approaches determining were compared. Values determined when Δδ 90% optimal whereas 75% resulting being be 8.47–8.71.

Language: Английский

Citations

0