From Pyridine-<i>N</i>-oxides to 2-Functionalized Pyridines through Pyridyl Phosphonium Salts: An Umpolung Strategy
作者:Dmitry I. Bugaenko、Marina A. Yurovskaya、Alexander V. Karchava
DOI:10.1021/acs.orglett.1c02165
日期:2021.8.6
The reactions of pyridine-N-oxides with Ph3P under the developed conditions provide an unprecedented route to (pyridine-2-yl)phosphonium salts. Upon activation with DABCO, these salts readily serve as functionalized 2-pyridyl nucleophile equivalents. This umpolung strategy allows for the selective C2 functionalization of the pyridine ring with electrophiles, avoiding the generation and use of unstable
吡啶-N-氧化物与Ph 3 P 在已开发条件下的反应为(吡啶-2-基)鏻盐提供了前所未有的途径。用 DABCO 活化后,这些盐很容易用作功能化的 2-吡啶基亲核试剂等价物。这种 umpolung 策略允许使用亲电试剂对吡啶环进行选择性 C2 官能化,避免产生和使用不稳定的有机金属试剂。该协议在环境温度下运行并耐受敏感的官能团,从而能够合成其他具有挑战性的化合物。