Preparation of diamines by lithiation–substitution of imidazolidines and pyrimidines
作者:Neil J. Ashweek、Iain Coldham、Thomas F. N. Haxell、Steven Howard
DOI:10.1039/b301502e
日期:2003.4.23
The synthesis of chiral 1,2-diamines and 1,3-diamines was achieved from the unsubstituted diamines by way of N-tert-butoxycarbonyl (Boc) substituted imidazolidines (tetrahydroimidazoles) and pyrimidines (hexahydro-1,3-diazines), which were treated with sec-butyllithium to effect deprotonation α- to the N-Boc group, followed by addition of an electrophile to give substituted products that could be hydrolysed under acidic conditions to give the substituted 1,2- or 1,3-diamines. Use of the chiral ligand (â)-sparteine promoted asymmetric deprotonation of the imidazolidine substrates to give, after hydrolysis, enantiomerically enriched 1,2-diamines.
通过未取代的二胺合成手性1,2-二胺和1,3-二胺的方法是,先使二胺与N-叔丁氧羰基(Boc)取代的咪唑啉(四氢咪唑)或嘧啶(六氢-1,3-二嗪)反应,再用仲丁基锂处理,使α位上的氢原子去质子化并与N-Boc基团反应,接着加入亲电试剂得到取代产物,后者在酸性条件下水解后可得到取代的1,2-或1,3-二胺。使用手性配体(-)-鹰爪豆碱能促进咪唑啉底物的非对称去质子化,水解后得到旋光纯度较高的1,2-二胺。