Modular Synthesis of Benzoylpyridines Exploiting a Reductive Arylation Strategy

Herein we disclose a telescoped flow strategy to access
electronically
differentiated bisaryl ketones as potentially new and tunable photosensitizers
containing both electron-rich benzene systems and electron-deficient
pyridyl moieties. Our approach merges a light-driven (365 nm) and
catalyst-free reductive arylation between aromatic aldehydes and cyanopyridines
with a subsequent oxidation process. The addition of electron-donating
and withdrawing substituents on the scaffold allowed effective modification
of the absorbance of these compounds in the UV–vis region,
while the continuous flow process affords high yields, short residence
time, and high throughput.