Borane-Methyl Sulfide Reductive Cyclization of ω-Ester Alkylamides: A Convenient Synthesis of N-Substituted Cyclic Amines

Article abstract of DOI:10.1055/s-1988-27777

Borane-methyl sulfide (BMS) reduction of variously N-substituted succinamic and glutaramic esters affords the corresponding N-substituted pyrrolidines and piperidines in high yields.The limitations, mainly caused by steric hinderance around the amine nitrogen, and putative intermediates involved in this conversion, as detected by incomplete reaction and/or synthesis followed by BMS reduction, indicate that cyclization and amide reduction successfully compete with ester reduction to afford the N-substituted cyclized amines.