The Suzuki-Miyaura Cross-Coupling Reactionsof 2-, 6- or 8-Halopurines with Boronic Acids Leading to 2-, 6- or 8-Aryl- and -Alkenylpurine Derivatives
作者:Martina Havelková、Dalimil Dvořak、Michal Hocek
DOI:10.1055/s-2001-16765
日期:——
The Suzuki-Miyaura cross-coupling reactions of 9-benzyl-6-chloropurine, 9- or 3-benzyl-8-bromoadenine and 2,6-dihalopurines with boronic acids gave the corresponding 6-, 8- or 2-aryl- or -alkenylpurines in good yields. Anhydrous conditions in toluene were superior for coupling of electron-rich boronic acids, while aqueous DME was used for electron-poor arylboronic acids as well as for alkenylboronic acids. A good regioselectivity was observed for the coupling of 2,6-dihalopurines: 9-benzyl-2,6-dichloropurine reacted with one equivalent of phenyl boronic acid to give 9-benzyl-2-chloro-6-phenylpurine, while an analogous reaction of 9-benzyl-6-chloro-2-iodopurine gave selectively 9-benzyl-6-chloro-2-phenylpurine.
9-苄基-6-氯嘌呤、9-或3-苄基-8-溴腺嘌呤及2,6-二卤嘌呤与硼酸进行的铃木-宫浦交叉偶联反应,以良好产率得到了相应的6-、8-或2-芳基或烯基嘌呤衍生物。无水条件下以甲苯为溶剂对于富电子硼酸的偶联反应较为有利,而贫电子芳基硼酸及烯基硼酸则以含水的二甲氧基乙烷(DME)为溶剂进行反应。在2,6-二卤嘌呤的偶联反应中可以观察到良好的区域选择性:9-苄基-2,6-二氯嘌呤与一当量苯硼酸反应得到了9-苄基-2-氯-6-苯基嘌呤,而9-苄基-6-氯-2-碘嘌呤的类似反应则高选择性地得到了9-苄基-6-氯-2-苯基嘌呤。