Efficient Synthesis of α-Aryl Esters by Room-Temperature Palladium-Catalyzed Coupling of Aryl Halides with Ester Enolates
作者:Morten Jørgensen、Sunwoo Lee、Xiaoxiang Liu、Joanna P. Wolkowski、John F. Hartwig
DOI:10.1021/ja027643u
日期:2002.10.1
arylation of alpha,alpha-disubstituted esters were developed with LiNCy(2) as base and P(t-Bu)(3) as ligand. In addition, tert-butyl esters, such as those of Naproxen and Flurbiprofen, were prepared from tert-butyl propionate and aryl bromides in high yields in the presence of Pd(dba)(2) and the hindered, saturated heterocyclic carbene ligand precursor.
催化量的 Pd(dba)(2) 由卡宾前体 N,N'-双(2,6-二异丙基苯基)-4,5-二氢咪唑鎓 (1) 或 P(t-Bu)(3) 介导芳基卤化物和酯烯醇化物在室温下以高产率偶联产生α-芳基酯。该反应对芳基卤化物上的官能团和取代模式具有高度耐受性。使用 LiNCy(2) 作为基础和 P(t-Bu)(3) 作为配体开发了用于选择性单芳基化乙酸叔丁酯和 α、α-二取代酯的有效芳基化的改进方案。此外,在 Pd(dba)(2) 和受阻饱和杂环卡宾配体前体存在下,由丙酸叔丁酯和芳基溴化物以高产率制备叔丁酯,例如萘普生和氟比洛芬。