.png){kind=icon}
.png){kind=icon}
Return
Diversifying Trityl Radicals via Oxidative Radical-Polar Crossover in Tandem with Aromatic Nucleophilic Substitution
.png){kind=icon}
PRE
AI
X
J
Z
Y
G
C
T
刘
Y
DOI：10.1021/acs.joc.5c03184.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Tetrathiatriarylmethyl (trityl) radicals are key spin probes for electron paramagnetic resonance (EPR) spectroscopy and crucial building blocks for high-performance dynamic nuclear polarization (DNP) agents. However, their applications have been limited by complex synthesis and structural modifications. In this study, we address this limitation by developing an oxidative radical-polar crossover (ORPC) strategy for trityl derivatization. This approach utilizes oxidization of trityl radicals by nitrosyl tetrafluoroborate (NOBF4) to the corresponding trityl carbocations, which subsequently undergo aromatic nucleophilic substitution (SNAr) with a diverse range of nucleophiles to afford various trityl derivatives. This method exhibits several notable advantages: (1) wide substrate scope, compatible with N-, S-, P-, and C-centered nucleophiles, including water-sensitive organozinc reagents; (2) high regioselectivity for monofunctionalization of a single aryl ring, avoiding statistical reaction mixtures; (3) iterative ORPC reaction which enables the synthesis of both symmetric trityls with three identical substituents and asymmetric trityls with three distinct substituents; (4) significantly improved yields which are 1.5-2 fold higher than those reported in the literature. This straightforward approach provides a powerful tool for tailoring trityl radicals to advance their applications in the fields of EPR and DNP.
Keywords:
ELECTRON-SPIN RELAXATION
LARGE-SCALE SYNTHESIS
TRIARYLMETHYL RADICALS
DISTANCE MEASUREMENTS
TRIS(2,3,5,6-TETRATHIAARYL)METHYL CATIONS
TISSUE OXYGEN
250 MHZ
EPR
PROBE
PH
Journal
IF:
3.6
Papers:
5.4W
Citations:
8.8W
Organization
Cited Papers