钯催化咖啡因C—H键直接烷氧基羰基化反应生成8-酯基咖啡因衍生物

Palladium-Catalyzed C—H Alkoxycarbonylation of Caffeines:Synthesis of 8-Ester-substituted Caffeines

咖啡因羰基衍生物在药物活性及生物荧光方面表现优异性能,其简便合成方法备受关注.从咖啡因C—H键直接出发,研究了过渡金属钯配合物催化咖啡因C—H键与醇的氧化羰基化反应.以Pd Cl_2(PPh_3)_2为催化剂,以醋酸铜为氧化剂的反应体系下,不同咖啡因衍生物与不同醇均能进行氧化羰基化反应,得到了一系列8-酯基咖啡因衍生物.反应所用CO为一个大气压,操作简便,溴、烯烃和苯环等官能团都与体系有很好的兼容性.

Carbonyl-substituted caffeine derivatives have attracted much attention due to their potent pharmaceutical activity and interesting fluorescent properties. An efficient synthesis of 8-ester-substituted caffeines through palladium-catalyzed C--H alkoxycarbonylation was developed. The reaction was carried out in the presence of PdCl2（PPh3）2 and Cu（OAc）2 under 101 kPa CO atmosphere in 1,4-dioxane, providing diversified 8-ester-substituted caffeines in reasonable to good yields. The ap- proach was characterized by using atmospheric pressure of carbon monoxide and broad functional group tolerance.