A methodology for the synthesis of (E)-6-alkenylpurines, starting from 6-iodopurines, based on a Pd-catalyzed stannation/protodestannation protocol, is described. The alkynylation reactions were catalyzed by Pd(OAc)2/PPh3 in acetonitrile. The Pd-catalyzed stannation itself provided a mixture of Z regioisomers but following protodestannation using TFA induces Z to E isomerization giving (E)-6-alkenylpurines. The reactivity of other 2- and 8-alkynyl purines has also been studied.
介绍了一种从6-碘嘌呤出发,基于Pd催化的锡化/脱锡化协议,合成(E)-6-烯基嘌呤的方法。炔基化反应在乙腈中由Pd(OAc)2 / PPh3催化。 Pd催化的锡化本身提供了混合的Z-异构体,但是使用TFA进行脱锡化后,引发了Z到E的异构化,从而得到(E)-6-烯基嘌呤。还研究了其他2-和8-炔基嘌呤的反应性。