A General and Efficient 2-Amination of Pyridines and Quinolines
摘要:
Pyridine N-oxides were converted to 2-aminopyridines in a one-pot fashion using Ts2O-t-BuNH2 followed by in situ deprotection with TFA. The amination proceeded in high yields, excellent 2-/4-selectivity, and with good functional group compatibility. 2-Amino (iso)quinolines were also obtained in the same manner. Combined with the simple oxidation of pyridines to pyridine N-oxides, this method provides a general and efficient way for amination of 2-unsubstituted pyridines.
A new strategy is developed for the synthesis of 1-aminoisoquinoline derivatives. This Rh(III)-catalyzed [4 + 2] annulation reaction employs benzamidines as efficient directing groups and the vinylenecarbonate as an acetylene surrogate. Additionally, the reaction features broad substrate scopes and good yields, only producing carbonate anion as byproduct.