Enantioenriched synthesis of Escitalopram using lithiation–borylation methodology
作者:Benjamin M. Partridge、Stephen P. Thomas、Varinder K. Aggarwal
DOI:10.1016/j.tet.2011.09.142
日期:2011.12
The asymmetric synthesis of Escitalopram has been completed using a lithiation–borylation reaction as the key step. Suitably functionalized enantioenriched carbamate (er 98:2) and boronic ester coupling partners were prepared and following deprotonation with s-BuLi and borylation, the tertiary alcohol was obtained in 42% yield and 93:7 er. The lithiation–borylation reaction was found to tolerate nitrile
艾司西酞普兰的不对称合成已通过锂化-硼化反应作为关键步骤完成。制备了适当官能化的对映体富集的氨基甲酸酯(er 98:2)和硼酸酯偶联剂,在用s -BuLi脱质子化并进行硼酸酯化后,以42%的收率和93:7 er的价格获得了叔醇。发现锂化-硼化反应可耐受腈,苄醇和N -Boc官能团。在另外三个步骤中将叔醇转化为依他普仑。