Diversity-oriented synthesis of acyclic nucleosides via ring-opening of vinyl cyclopropanes with purines

The diversity-oriented synthesis of acyclic nucleosides has been achieved via ring-opening of vinyl cyclopropanes with purines. With Pd-2(dba)(3)center dot CHCl3 as a catalyst, the 1,5-ring-opening reaction proceeded well and afforded N9 adducts as the major form, in which the C=C bonds in the side chain were exclusively E-form. In the presence of AlCl3, the 1,3-ring-opening reaction occurred smoothly, giving N9 adducts as the dominate products. Meanwhile, when MgI2 was used as the catalyst, the 1,3-ring-opening reaction also worked well to form N7 adducts.