From Pyridine-N-oxides to 2-Functionalized Pyridines through Pyridyl Phosphonium Salts: An Umpolung Strategy

• DOI: 10.1021/acs.orglett.1c02165
• Publication Date: 2021-07-16T13:11:49Z
• Authors: Dmitry I. Bugaenko; Marina A. Yurovskaya; Alexander V. Karc...
• Keywords: Umpolung; Phosphonium; DABCO; Phosphonium salt; Surface Modification

The reactions of pyridine-N-oxides with Ph3P under the developed conditions provide an unprecedented route to (pyridine-2-yl)phosphonium salts. Upon activation DABCO, these salts readily serve as functionalized 2-pyridyl nucleophile equivalents. This umpolung strategy allows for selective C2 functionalization pyridine ring electrophiles, avoiding generation and use unstable organometallic reagents. protocol operates at ambient temperature tolerates sensitive functional groups, enabling synthesis otherwise challenging compounds.