Ruthenium Complex Catalyzed N-Heterocyclization. Syntheses of N-Substituted Piperidines, Morpholines, and Piperazines from Amines and 1,5-Diols

Article abstract of DOI:10.1021/jo00209a004

1,5-Pentanediol reacts with aliphatic and aromatic primary amines in the presence of a ruthenium catalyst modified with phosphonic ligands to give N-substituted piperidines in fair to goods yields.The reactions were carried out at 150-180 deg C for 5 h in dioxane.The nature of the phosphorus ligands has a remarkable effect on the catalytic activity, For the reaction of aromatic amines, triphenylphosphine is effective, while for aliphatic amine more basic tributyl- or triethylphosphine is preferable.Amines also react with diethylene glycol and N-substituted diethanolamines in the presence of the ruthenium catalyst to give N-substituted morpholines and piperazines in good yields, respectively.