RESUMEN
Electron-transfer photocatalysis provides access to the elusive and unprecedented N-pyridyl radical cation from selected N-substituted pyridinium reagents. The resulting C(sp2 )-H functionalization of (hetero)arenes furnishes versatile intermediates for the development of valuable aminated aryl scaffolds. Mechanistic studies that include the first spectroscopic evidence of a spin-trapped N-pyridyl radical adduct implicate SET-triggered, pseudo-mesolytic cleavage of the N-X pyridinium reagents mediated by visible light.
RESUMEN
A simple trifluoromethoxylation method enables non-directed functionalization of C-H bonds on a range of substrates, providing access to aryl trifluoromethyl ethers. This light-driven process is distinctly different from conventional procedures and occurs through an OCF3 radical mechanism mediated by a photoredox catalyst, which triggers an N-O bond fragmentation. The pyridinium-based trifluoromethoxylation reagent is bench-stable and provides access to synthetic diversity in lead compounds in an operationally simple manner.
RESUMEN
This report describes the development of an enantioselective C-N bond-forming reaction to produce 1,2,3,4-tetrahydroisoquinoline-derived cyclic aminals catalyzed by chiral phosphate anions. Central to the success of this goal was the design of a library of 3,3'-triazolyl BINOL-derived phosphoric acids capable of forming attractive hydrogen-bonding interactions with the peptide-like substrate. We envision this work will offer an alternative to the conventional strategy of increasing catalyst steric bulk to improve enantioselectivity with BINOL-derived phosphoric acids.