Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technologies, University of Calabria , Via P. Bucci 12/C, 87036 Arcavacata di Rende (CS), Italy.
Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali, University of Messina , Via SS Annunziata, 98168 Messina, Italy.
J Org Chem. 2018 Feb 2;83(3):1680-1685. doi: 10.1021/acs.joc.7b03167. Epub 2018 Jan 18.
A novel carbonylative approach to the synthesis of functionalized 1H-benzo[d]imidazo[1,2-a]imidazoles is presented. The method consists of the oxidative aminocarbonylation of N-substituted-1-(prop-2-yn-1-yl)-1H-benzo[d]imidazol-2-amines, carried out in the presence of secondary nucleophilic amines, to give the corresponding alkynylamide intermediates, followed by in situ conjugated addition and double-bond isomerization, to give 2-(1-alkyl-1H-benzo[d]imidazo[1,2-a]imidazol-2-yl)acetamides. Products were obtained in good to excellent yields (64-96%) and high turnover numbers (192-288 mol of product per mol of catalyst) under relatively mild conditions (100 °C under 20 atm of a 4:1 mixture of CO-air), using a simple catalytic system, consisting of PdI (0.33 mol %) in conjunction with KI (0.33 equiv).
本文提出了一种合成功能化 1H-苯并[d]咪唑并[1,2-a]咪唑的新型羰基化方法。该方法包括在仲亲核胺存在下，对 N-取代的 1-（丙-2-炔-1-基）-1H-苯并[d]咪唑-2-胺进行氧化氨甲酰化，得到相应的炔酰胺中间体，然后进行原位共轭加成和双键异构化，得到 2-（1-烷基-1H-苯并[d]咪唑并[1,2-a]咪唑-2-基）乙酰胺。在相对温和的条件下（在 20 大气压的 CO-空气 4:1 混合物中 100°C），使用简单的催化体系（PdI（0.33 mol %）与 KI（0.33 当量）的组合），在温和条件下（在 20 大气压的 CO-空气 4:1 混合物中 100°C），使用简单的催化体系（PdI（0.33 mol %）与 KI（0.33 当量）的组合），以良好至优异的收率（64-96%）和高转化率（每摩尔催化剂 192-288 摩尔产物）得到产物。
