Development of Efficient Catalytic Systems Based on the “Borrowing Hydrogen” Methodology for Regioselective Alkylation of Heterocyclic Compounds and Synthesis of Amino Alcohols

Abstract

Our efficient catalytic reactions based on the “Borrowing Hydrogen” methodology are described here. Thus, indoles were reacted with alcohols in the presence of Pd/C or RuCl₂(PPh₃)₃/DPEphos catalyst to give the corresponding 3-alkylindoles in good to excellent yields. The Pd/C catalysis also promoted the regioselective alkylation of 4-hydroxycoumarin, barbituric acids and oxindoles with good catalytic efficiency. Reaction of amines with 1,2-diol in the presence of [RuCl₂(p-cymene)]₂/JOSIPHOS catalyst afforded the optically active β-amino alcohols with up to 77% ee. Highly efficient hydroamination of C-C double bond of allylic alcohols was achieved with a combination catalyst of RuClH(CO)(PPh₃)₃ and a pyridine ligand bearing two imine units at its 2,6-position to provide the corresponding γ-amino alcohols in high yield.