The reactions of dioxanyl and cyclohexylradicals with 2- and 3-X-pyridines (X = CN, COMe, CO2Me) give a single substitution product deriving by addition at the 5- and 6-positions respectively; with 4-X-pyridines substitution occurs preferentially at the 3-position. If the reactions are carried out with protonated pyridines other positional isomers are obtained. From the synthetic point of view the
Transition-metal-free cross-dehydrogenative alkylation of pyridines under neutral conditions
作者:Xin Li、Hao-Yuan Wang、Zhang-Jie Shi
DOI:10.1039/c3nj00095h
日期:——
A mild and efficient method has been developed for the direct dehydrogenative alkylation of unprotonated pyridine derivatives. The avoidance of using acids and transition-metals makes this protocol “greener” and more practical for the synthesis of substituted pyridines.