An efficient, environmentally benign, transition-metal free, tandem C–N, C–O bond formation reaction is developed for the synthesis of tricyclic 7-oxa-2-azatricyclo[7.4.0.02,6]trideca-1(9),10,12-trien-3-ones and their homologs from easily available starting materials, including renewable levulinic acid, a keto acid. The reaction of keto acids with methyl chloroformate and variously substituted o-aminobenzyl alcohols using triethylamine as a base in toluene at room temperature gave good to excellent yields. This newly developed protocol was successfully utilized for the synthesis of a variety of polycyclic 7-oxa-2-azatricyclo[7.4.0.02,6]trideca-1(9),10,12-trien-3-ones and related compounds.
开发了一种高效、环境友好、无需过渡
金属的串联C-N、C-O键形成反应,用于从易于获得的起始原料,包括可再生的
乙酰乙酸,一种
酮酸,合成
三环7-氧杂-2-氮杂
三环[7.4.0.0²,6]十三碳-1(9),10,12-
三烯-3-酮及其同系物。
酮酸与
氯甲酸甲酯和各种取代的邻
氨基
苄醇在
甲苯中室温下使用
三乙胺作为碱进行反应,产率良好至优秀。这一新开发的方案成功地应用于合成多种多环7-氧杂-2-氮杂
三环[7.4.0.0²,6]十三碳-1(9),10,12-
三烯-3-酮及相关化合物。