Borane-Methyl Sulfide Reductive Cyclization of ω-Ester Alkylamides: A Convenient Synthesis of<i>N</i>-Substituted Cyclic Amines
作者:Michael C. Venuti、Oswald Ort
DOI:10.1055/s-1988-27777
日期:——
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.
硼烷-硫化甲基(BMS)还原各种N-取代的琥珀酰胺和戊二酰胺酯,可以高产率地得到相应的N-取代吡咯烷和哌啶。这一转化过程中,由于胺氮周围的空间阻碍限制,以及通过不完全反应和/或合成后续的BMS还原检测到的假定中间体,表明环化作用和酰胺还原成功地与酯还原竞争,从而得到了N-取代的环化胺。